It's most likely possible. I got to Lv23 before getting the Battle Tower, and could've reached 24 if I wanted to. At Lv24, taking on some Lv27 enemies wouldn't be a huge deal, assuming one assigned skill points effectively and used powerful enchanted items.
I also got Lv9 Increase Damage and Increase Magic Damage enchantments, and dual-wielded Brightblade and Tagos' Axe, which gives a HUGE damage boost. So it's definitely possible, but requires a lot more effort than it's worth.
