Is it normal to fear i would be a bad significant other?

I think that maybe you feel you wouldn't live up to the ideals of romance, but those fairytale ideals don't exist in reality. All you need to be able to feel is love toward somebody. If you get hung up on how it's supposed to be expressed, you're not loving, you're just going through the motions. Everything about love and romance should be natural, so you'll only know how you'll experience it and what parts you'll play when it happens. If it's meant to be, it will be. You're more than one somebody's perfect match. And all you need to find is one of them.

There is somebody out there for each of us. In fact, there are probably quite a few out there who would be a great partner for you.
First thing you need to do is see yourself in a better light. You are probably much more attractive and sexy than you think. You may "dress down" wearing baggy clothes to hide your body and walk without any confidence, all of which can further reduce interaction with others. Have you ever heard, "dress for success"?
Relax, open up to the possibilities life offers and make yourself available to advances from people. Show (even if you don't feel it, in the beginning) confidence, and try a new wardrobe. Be who you are; you are a worthwhile person to know, and others will want to know you.

Love and being a good significant other doesnt mean you have to follow the social normals aka how relationships are in the media.

Story of my life OP.. You could do it, but you'd have to make more of a conscious effort to carry your part in the relationship and make sure you're aware of each others' needs, since you're not someone who it comes to naturally. If you can manage that it will be fine but communication has to be there. Also strongly avoid people who will put pressure on you, i.e. to be more social or feminine.

Secondly I think just the fact that you're an individual and different will make you attractive to someone. You're not unfit for love OP it just takes more effort for some than others.

I get what you're saying about not being "wired" for romance. I'm the same way. I also have trouble expressing emotion or even understanding it.
I actually have a really fun personality and girls seem to like to spend time with me but anything beyond casual friendship I am completely confused about.

I've noticed girls give me attention while in groups but often avoid my invites to hangout alone somewhere. I think they might be afraid of me because I've been told that a lot. I'm eccentric but I'm friendly so I don't know why some girls don't want to come to my house or on a date. They usually say yes and I get stood up 9/10 times and I cannot figure out why. The 1/10 time usually goes horribly even though I got along with them in the group.

I have had a couple girlfriends in the past, who I still get along with great as friends, but in a relationship I did not make them happy. I am awful to live with but fun to hangout with. My ex's would get upset with me because I could never tell when they were upset and I don't think I will ever be able to deal with the stress that a relationship causes me again.

I get along with people pretty good but I also don't like being too close to anyone. I like to keep my friends and family at a distance but I do like to spend time with them too. I just want to be alone at the end of the day.