Unfortunately there's no way to tell- it took me several months. Depends on your internal's circumstances. Follow-up with him every 3 weeks or so is my suggestion. I've been there and know how frustrating it can be. If you don't hear back in time it's ok you'll just graduated officially later than what you had in mind. I ended up graduating 2 months after when I had hoped to graduate. In the great scheme of things tbh, it's not a big deal.