Im thinking of joining a baseball club here in Melbourne Australia. Help?

the problem is i dont know how to play the game. my throwing and batting skills is not that good compared to pro players. Baseball is not a big thing here in Australia. But i realy like the game. Im also afraid that other players might make fun of me. Or they might just ignore me. The reasons why i wanna join a baseball club is because. I wanna be fit and healthy. I realy want to loose weight. Im in year 10 and i weight about 64kilos. I also want bigger biceps and to be more mascular. And everyone in my school are doing Afl football, cricket, soccer. But i dont know anyone who plays baseball im also scared that people at my school will make fun of me playing baseball. Im now 15 if that helps..