Am I on track?!

Four weeks ago I injured my knee doing competitive aerobics landing in the splits. An MRI showed a complete ACL tear but luckily no other damage to the knee. 9 days ago I had an ACL recon using my hamstring tendon. The surgery went well, I was sent home the next morning with just a tube bandage and crutches and told to come off them ASAP. The pain was minimal and by the third day I was hobbling around. For the 3 weeks before surgery I unable to completely straighten my knee. I have been doing my exercises religiously since the op but am still about 10 degrees away from full extension, but have achieved 90+ degrees flexion. Essentially my leg won't go any straighter than before I injured it. Should I be concerned so early? I'm petrified of never regaining full extension. Please share your experiences!!