I took a MRI and it says :posterior horn of the medical meniscus with partial tear of the meniscocapsular. Would I need surgery or just brace my knee?

Surgery? The injury you are describing in someone your age would likely require surgery. Symptoms of locking, catching, persistent swelling and pain are clear indicators. There are cases where menuscal injuries are treated non-surgically. A sports medicine physician or orthopedic surgeon can help determine which option is best for you.