Will lifting weights make me a better baseball player? If so how do I ask my parents for a gym membership?

I'm 15 and in high school I'm pretty small muscular wise but I'm wondering if lifting weights and working abs will help me to throw hard and farther? Hit harder and farther? Make me faster? Quicker? I want to put on lean mass and still have a 6 pack and try outs are in end of february. How many pounds of muscle will I gain lifting two days resting ome day? How do I ask my parents fir a gym membership I'm scared and embarrassed to ask them,. What exactly do I say?