Is it normal i don't know what to tell my little cousin

Explain to her that you went through the same thing so she knows that she is not alone. Then tell her that she is young and that her sexuality is still developing and that she has all of the time in the world to figure this out, there is no hurry. Assure her that you will love her no matter what and tell her that her feelings are natural but she should wait until she is sure of her sexuality and of her feelings before talking to her friend. Please let her know, though, that the friendship could be risked if her friend is unable to understand which is possible as her friend is also young.

She is too young to be worring about her sexuality! She probably doesn't know what 'in love' really means. She has just heard adults talking about it. Girls of her age are concerned with friends and best friends. Maybe she is confusing 'best freind' with being 'in love'.
Don't talk to her about sexuality until she is A LOT older.

There was a similar case a while back with a girl about a year older, i'll basically just copy/paste one part here:

-----
factually, in this age, it's almost impossible to tell.
Girls who become wild lesbians 10 years later will have silent crushes on guys and act all shy.
Others will experiment with their girlfriends but end up marrying a guy as virgin a couple years later.
It's a time of hormonal crazyness, and everything goes, and being confused about one's own "orientation" is normal.
So a girl-crush, even if it turns into a sleepover with homosexual experimentation, nowhere near suggests that she either will be bisexual or a lesbian later on.
Neither does it mean that a girl that goes through this phase without even thinking about another girl theoretically will end up being straight later.

:)
So ya, it's her hormones being crazy and at her age, it's impossible to tell ANYTHING for sure.
-----

As for what to tell her, it's hard to say. A whole lot would depend on her own personality as well as that of her friend.
I know her situation well. I decided to keep silent and the crush to myself. Did i regret it? Kinda, but i was afraid of all the things that could go wrong.

While bi- or homosexuality is way more accepted nowadays, she'd still get people either verbally assaulting her, telling her she's just confused, avoiding her, the whole thing.
While i think everybody should be free to be themselves, in some cases it's not worth paying the price...but thats a case-to-case decision, and not a universal truth. It's a fact that many will see her as a "kid" though, and kids can't even consent, so will never be taken serious about their sexual choices...that changes only with age.

I'd say go with your instincts, and above all, be there as a friend she can confide in. Don't do things like avoid her just because you don't know how to handle it or what to tell her. If i know one thing, then that she needs someone to be with her on this, no matter how it turns out.

Well she is 12 YEARS OLD, for fuck's sake. If she does announce that she is a lesbian at that age, take it with a grain of salt because someone that age does not always know their sexuality yet. Maybe she will end up liking other women as an adult, but maybe not. If she were older, like say 15 or 16 I'd say that she probably will always be attracted to other women and probably does genuinely like her friend. However, even at that, sexuality is a lot more malleable than most people think it is even for people much older. Although, if she were older than say 15 I'd say that chances are she always will be attracted to women.

Hah apparently this has happened to lots of people.

It's so hard... society has so many labels for things, and she's probably trying to fit herself into those.

I also think society tends to sexualize everything. Over the years I've learned to differentiate romance from sex.

But anyway. I'd say... In your shoes I would try to laugh/ add humor to it. Let her know it's not a big deal. That's what I did with my cousin : ) Worked pretty well.

The same thing happened to me! Definitely tell her your story and that it happens to a lot of people. I've found out that I'm bi and have the capacity to be attracted to both genders but what happens now doesnt necessarily mean anything for her sexuality later in life. Don't encourage her too much to tell the friend because if she did and the friend rejected her (which is kind of what happened to me) it could be really hurtful.

Be careful! x

Sheesh, what's to tell her? She's a kid!

Tell her your story, and that she's not the only one.

Main thing is to let her know not to be ashamed of who she is. Also tell her that you are there to support her, no matter what. There is nothing worse than feeling scared and alone when dealing with issues like this.
The best friend problem is going to be a tough one for her to work out, so give her guidance in the form of your story and be there for her no matter what she chooses to do.

Just tell her your story.
I'm sure it will calm he to know that you also went through that and make her own decision based on what you tell her.

Give her a dildo.