It is questionable whether you merely tore your medial collateral ligament (MCL) when you were first hurt. Had you only injured the MCL, chances are it would have scarred down and not given you much trouble.
From what you describe, it is more likely that you also stretched or tore the anterior cruciate ligament (ACL). In either case, you might not be a candidate for ligament surgery given your age. Instead, a surgeon specialist will probably want to have you use a brace and do exercise treatments. If these aren't helpful, surgery might be a last resort.
Age is one factor your surgeon will consider. So is activity. Your surgeon may treat you as he or she would a younger patient, given your level of activity.