Conservative care before surgery won't hurt and may help. In fact, a rehab program can get you back on your feet sooner -- if the knee is stable enough to play without surgery. It's important to wear your brace as prescribed. Protecting the joint from further damage during this healing and recovery period reduces the risk of reinjury.
Early surgery does have some advantages. For one thing, it is a faster way to return to full activities. Having surgery right away puts you into rehab that much sooner. The initial delay is no longer an issue.
Another advantage of early ACL reconstruction is avoiding further damage to the cartilage and other ligaments in the knee. If you return to sports activity with an ACL-deficient knee, you are at increased risk of cartilage injury. A small meniscal tear can become a full-thickness tear. This is especially true if the joint is subjected to trauma or force during the recovery period.
Your surgeon can really guide you in making the best decision for your particular situation. The results of your examination and imaging tests will help identify your risks and the treatment approach best suited to the specifics of your injury.