Hey! I've been writing for about 7 years now. I can honestly say I've improved, but I'm still not what you may call "A pro" (Maybe 15 is a little young to worry about that, though-I'm not Christopher Paulini!). It all began when I was in 5th grade, and my friend and I started to write a book for no reason. After that I began to love the craft and now write on a daily basis. I still have a long way to go but hope to meet you all and have fun on here! Thanks!
Welcome! Worry about being a pro at whatever age you feel you're ready. It's about strength of writing, which grows over time but at different rates for different people, and has far more to do with how much you write (and read) than it does with age. But you write every day, so you're on the right path!
+1 for Mallory's post! I'd also add that in addition to writing and reading it's about the experience you gain. So do get out there and open up your senses.
Alright, thanks guys! @Mallory Yeah, on a daily basis. I used to write on some other anime forum, but realized that wasn't a place to get good critism. So thanks for all the welcomes. But just one question-can't seem to be able to make a new thread :/. Do I have to wait a certain amount of time?