You'd get so 17 additional skill points at the absolute best if you stealthed it from level 3 and bought the respawns at every level up.
You don't have to go there lvl 3. Vendor re-stocks them outside of lvling up. You aren't limited to 17 either. I purchased one set at lvl 11, and 3 sets now at lvl 12. The vendor reset is both time and lvl based. Also as the other poster said, it's 3 points per skill book, not one, that you get so (17 x 3 = 51) assuming you only got them at lvl up.
