I don't think they'll take you seriously no matter what. You're still quite young and the possibility you'll change your mind as you get older is really high. And be open minded because once life starts throwing things at you, you'll change as a person. You have no idea what's out there in the world.
So just tale your time with your sexuality. Once you grow up and start dating girls, I'm sure your mom will get the message that you're a lesbian loud and clear.

They don't have to take you seriously. It's your sexuality, the only person that matters is you.

That being said, at 13 you often do not know what you do or do not want. Maybe perhaps YOU do, but you have to appreciate that you would be the exception, not the rule. While it is frustrating to have a close loved one (parent) or your therapist not believe your honest words, can you really hold them at fault for following what seems reasonable considering the circumstances?

Quite honestly, the only thing that will convince them is time and the slow realization that this isn't some phase for you. But, don't be too concerned with their views. Just focus on how you see yourself because that is all that matters.

They'll take you seriously when you're older and you've actually experienced more of the world. Right now, you're still an inexperienced child.

What you do in that case is prove your point to them. Rather than bitching and screaming about how unfair they're being why don't you go online and find studies that show that people start to embody their sexual preference around puberty. I'm sure there are thousands of them. If they continue to argue with the facts tell them that they are just delusional (look up the definition of delusion and point that out to them too so that they don't think you're just being inflammatory)

Tell them that even if you do change your mind in the future (and you probably won't so this is just a hypothetical) that's absolutely no reason for them to just brush it off as a phase. Even if it is a phase it's part of who you are, and for them to ignore it is for them to ignore you and what kind of psychological effect do they think that will have on you?

---------- Post added at 10:21 AM ---------- Previous post was at 10:20 AM ----------

Basically: Write them a paper like you would for a class using evidence and I guess personal experience as well. If they continue to not take you seriously then there's just no hope.

I hear you because nobody took my cousin seriously when she came out of the closet at your age. I'm not sure if it's denial or that people actually just don't believe her.

True she could have gone back to being heterosexual and that's what everybody though was it was just a phase but now over a year later there she is dating a girl so all I can say is don't let people tell you how to feel. If your unsure about your sexuality give it time and the answer will make itself known. I wish you the best of luck with your life as I know how rough thing's can be on a homosexual person.

somewhat close or far I'm in a similar situation ... now what to do...

Well, Kiyoki-chan, ask yourself,why it is important that they 'seriously' understand you? If you are a lesbian then you are lesbian, you don't need to convince anybody about that.except your girl right?

Of course they don't take you seriously. You're a kid... When I told my mom that I liked girls instead of guys when I was 13, she didn't take me seriously at all and thought I should be going to church!! Your family is just in denial. They will anything and everything to change your mind about your sexuaity, but don't let them... You can't help who you love... After years of convincing, my mom finally got in my head and I changed my mind about being with girls. I am now in a relationship with a guy of 2 years and it's amazing.
When you're young, things go on in your head and you get confused, and i think thats what you are, especially since you are so young. Like someone who previously comment said, you will eventually down the road change your mind. Let me tell you something, you do not know your sexuality until you have sex with them, i know that sounds weird but it's true.
For me, i was attracted to girls, but once i had my lesbian experience i was ihfy about the whole thing. Girls are just better as emotional support n a relationship and thats what i wanted.
I think you really need to think things through.