This is a reasonably common trope in East Asian fantasy fiction (not 100% the same, but rebooting into one’s past with all their adult knowledge) and the Western fandom community does indeed clutch their pearls about it!
the main issue with age gaps imo isn’t to do with life experience or knowledge, it’s the disparity in resources & social networks. If you have a teen’s life (under guardianship of adults, treated like a minor by associates) your mental age gives you very little leverage over “real” teens! Go forth!