I understand what you mean entirely because I am also in my teens and a female.
In my case, it took about a year for people (particularly men) to finally take me seriously. In fact, only now have people really started to look at my technique for tips. No one ever asks and I suspect that it's because I'm young and female, but they do look. I have to say that it caught me by surprise because once people start respecting you, they expect a lot of you. I am happy that people are beginning to respect me, but at the same time... there's an added pressure once people start to.
Before they did, I was always the butt of jokes. Not in a mean way, but it doesn't have to be mean to become bothersome. All the guys were always making comments about my being a girl and made a point to be gentle with me. No one ever chose me as an uke because they were afraid to hurt me and I always got criticism. The criticism was helpful, but what made me dislike it was how they went about giving it. Who likes being dismissed and treated as if the only thing I had ever done was lift a frying pan or play with my dolls?
In the end, I think it was my patience and tolerance that got me through it all. If someone tries to muscle you... who cares? You know what you can do and what you can't. That's the important part. Someone else's perception will not impede your growth. I learned to just ignore what people thought and went at my own pace. Eventually, your abilities will prove themselves and even if people don't actively acknowledge them, they will know.
Nowadays, people, especially the guys, like using me as uke.