I hit level 22 during the final fight, so perhaps you could hit that before the final fight, I would be surprised if you can hit level 23 though.
You get 2 attributes every level, +1 from investing into Polymorph, and two from the Bigger and Better talent.
You start with 2 combat skill points, then get 1 every level after that, and one from the All Skilled Up talent.
You get 1 Civil skill point at 1,2 and then every 4 levels (6,10,14, etc), and one from the All Skilled Up talent.
You get 1 Talent point at 1,3 and then every 5 levels (8,13,18, etc).

Spoiler:

You can become Sworn which will give your main character 2 attribute points, 2 combat skill points, and 2 talent points.
I do not know if this is a Fane only option and I don't know what happens if you use a Swornbreaker later.