You would need surgery if you want to participate in sports or you want to be active. If you can modify your activities and do therapy, you may get away without surgery. Since you are so young, I think surgery would help you. Surgery is required only for ACL insufficiency. MCL usually heals without surgery and the decision about LCL can be made at the time of ACL surgery if there are any
doubts regarding its necessity to be repaired/ reconstructed.