Is it normal to have much younger friends / feelings for fictional characters?

I don't think you're being intentionally predatory, but I do think you don't love your boyfriend nearly as much as habit makes you think you do. You said yourself that circumstances are preventing you from moving out and that it's a sexless relationship, so it's no wonder that your mind is casting about frantically for something -- and someone -- that is satisfying to you. Your brain is craving stimulation, and your BF isn't giving it to you even if you're in the habit of believing you love him.

There's something about roleplay, especially roleplay in a limited environment like an online game or fan community, that can really suck you in if you're dissatisfied with your personal life. Because you only see the things you want to see in it, it looks perfect. However, there's little substance to it. You're trying to sustain yourself on it, but it's unsustainable. You're starving emotionally, and to fill yourself up, you're consuming things with no nutritional value, psychologically speaking.

You also need to consider the fact that you're using others as tools. You aren't interested in any kind of relationship with them, as you say yourself; however, other people's feelings can get tangled, and you might encounter someone who develops feelings for you, or at least for the you who roleplays a particular fantasy or writes a particular fan fiction.

You deserve better than a relationship with no sexual spark. HE deserves better, for that matter. Love is more than a roommate who shares your taste in TV shows and whose privates you occasionally handle. It really is better to be alone and free than with someone who's an emotional place-holder for you.

Free yourself and him from an unromantic and sexless pairing, and you'll find that roleplaying won't have the same hold on you.

Another temporary solution might be to look for other groups with more mature roleplayers. You'd probably find it more to your liking anyway, and you wouldn't feel like a prowling cougar. It'd be a stop-gap, but it's still better than feeling out of place in your online community and in your own home with your boyfriend.

You can have a loving sexless relationship, but it really ought to be open sexually if so...

As for being predatory, I'd suggest simply making a point of not asking anyone their age and assuming they're as old as you're comfortable with. I routinely do smutty roleplay, and logically I think most of the people involved are likely fat old men, but I suspend my disbelief and let myself pretend otherwise.

And I mean come one, do you think these girls are somehow getting hurt by your actions? If you do, stop, but it ludicrous to think so.

I understand how you feel, I'm only 20 and often think "well shit, I'm like way older than everyone else doing this shit" because often it seems like fandoms are made up of 14-17 year olds. I don't know if there's a secret grown-up website for people overage lol, but you didn't do anything with the girls once you learned how old they really are, so you are definitely not a pedo.

ProseAthlete, thank you so much for your reply. That was a very well-written post and it actually offered me a lot perspective about my situation from a person who sees things from a different vantage point.

Shrunk. thank you for your reply as well. I haven't forced or coaxed anyone into doing anything. It was one of the fangirls on my Tumblr who initially suggested that we roleplay and I responded to her by saying that "I guess it wouldn't hurt to try". That was before I realized she was underage.

And now that I do, all I can think of is unfollowing her and getting the hell away from her (as well as the other underaged fangirls). That's almost the entire community, though, but I digress.

I just feel like crap right now because I told her one of my dirty fantasies, and agreed to role play with her (before realizing she was 17) and from her following messages to me, and the fact that all of her RP story lines suddenly and inexplicably went from dirty smut to completely PG and sterile after her conversation with me, I felt that she was subtly implying that she was uncomfortable with me, with RPing with me (after she had first suggested it), that I was some sort of pervert (by her use of the word "gross" when referring to my fantasy, even though it was on par with some of the smut she used to frequently write about / RP, and by how the whole thing has turned out and some of our mutual friends that she normally RPs smut with have also changed their dirty RPs to completely sterile and PG after our conversations.

I don't know what she has told them about me or if she has indeed been gossiping about me to her friends / our mutual friends but I certainly hope she hasn't been putting a spin on things and making me out to be this "gross, dirty, perverse, predatory creep or pedophile".

The strange thing is, after all of these events have transpired, she suddenly started following me / my blog and I just feel so awkward and uncomfortable with her. We both also share mutual friends (whose age I don't know because I haven't asked) who I would like to keep as followers otherwise I fear that I may eventually be left with a dead blog and completely alienate myself from a vast portion of that particular fandom / fan community.

Keep in mind that I've already unfollowed her once and then re-followed her recently and apologized to her for unfollowing her because of a misundertanding / glitch with facebook (I didn't get a prompt when she replied to my mail and thought she was ignoring me so I took her off my list - then when I checked my inbox, it turns out she has replied to me and was very pleasant and polite so I followed her again and explained the whole thing). This was before I knew her age and now I want to unfollow her. Even if it makes me look like a crazy or unstable person with split personality or just a painfully indecisive person but I fear that if I do unfollow her, then it would cause her friends / our mutual friends to think that there is any merit to any of the things she may or may not have said about me behind my back or that she would even go and spin some tripe about me or even add a lot of false details to her story to make me look bad because I unfollowed her for the second (and last time).

I know this all sounds very complicated with all of the following and unfollowing shenanigans but I appreciate you all taking the time to read this far.