When I went to U of Chicago, my grades went to my parents and the bills were sent to me. I could never figure that out.
I always had an issue with the bills and financial stuff being sent to my daughters. If I am the one filling the forms out and paying then send the information to me. Forwarding information is not maturity, its just inefficient. By the time the kids and the ex got through with everything, I would spend 3 hours on the phone getting everything fixed back to the beginning so it could be done correctly.
Checking your emails is not a very high bar for maturity. But I agree, as a parent, you shouldn’t be meddling in your kid’s email.