Stars live a lot longer than a few million years, so that isn't necessarily true. In fact, we can guess pretty accurately whether the star is still alive based on which part of its life-cycle it was in when it fired off the light we are looking at. Wishing on a star is still bullshit though.

If they mean "wishing upon the shooting (or falling) star", then it is not true. Shooting star is not star at all, it is a piece of debris of a meteors, or just space rocks and dust, which enter Earth atmosphere at high speeds, heat up and burn. So when you wish on a shooting star it is actually happens right at the same moment. It still makes wishing on shooting star bullshit, as your dreams, but it has nothing to do with stars.