Experience honestly doesn't matter as much as a lot of other RPGs. Your level basically only affects your health and PP--pretty much everything else is governed by your stats and skills. Your stats, at least, appear to be pretty exceptional. Many characters finish the game with less health than you have right now. You shouldn't have any trouble clearing the air temple unless you get very unlucky.
Levelling is normally very boring in ADOM, and grinding for levels usually isn't very worthwhile. Most of your experience will come from a handful of monsters a little deeper down. If you're going for a regular ending, you might not finish at level 50, but you should be on pace to an easy win in the late 30s.
Hoping to win with every class, doomed. Archer, Barbarian, Bard, Beastfighter, Druid, Elementalist, Farmer, Fighter, Monk, and ULE Priest down.