I think it's important to let people know that there are fewer managers than workers. (At least, if a company is doing things correctly there are fewer management positions.) This means that not everyone will be able to make this transition even if you have the appropriate skills and disposition. Furthermore, if you look around a lot of tech companies, you'll notice that most of the managerial staff is <45 as well. So keep that in mind.

Basically, don't bank everything on going into management. Be financially responsible. Live beneath your means. Explore other pass times and activities that you may have an interest in pursuing in the future. The worst thing you can do is arrive at 40 or 45 with a Plan A that may not work out and no Plan B or C.