I've tested this out, and without point buy, it's overpowered. I'll probably tinker with it more, but I'll just keep the previous attribute amounts for now.
Even if I capped stats at 20 and made it so the player starts with 12 points to spend, this means you can have +5 attack bonus and +5 AC at level 1, 40+ health at level 1, etc with a starting attribute of 8.