I have had muscular atrophy in both of my legs i had it my whole life and i'm 19 now my mom said i have it because i was born premature will it ever go away?

Have you ever been evaluated by a neurologist? If no, you need to be seen if you truly have muscular atrophy. Premature alone should not cause muscular atrophy of the lower extremities. If you do not have any other symptoms along with muscular atrophy and your leg motion is normal, your leg muscles may be small but but not atrophic, trained exercise will improve that.