I'd recommend 16-ish if you're wanting to stand even a little chance without ragetonic, which you get at 22.

Why 16? You get howl at 16 which gives you a debuff as well as some damage.

The build I would go with is:
32 str (enough for l10 hammer pack)
51 Dex (extra hit% and enough for Dex ring)
1 Rabid Bite
1 Vixen Kick
5 Evasion (why not 6? It doesn't give extra armor as well as dodge from 5-6 and only 2 dodge difference)
2 fury (hammer at this level with foxes have low hit%)
4 hamstring (Found higher ham helps with healing classes like rhino/mages at this level for the high chance of stuns)
1 needle/dart whichever fits your preference.
1 howl (for the debuff)

Armor Preference: L5 armsman Crafted for the dodge. Foxes rely on dodge low brackets.
L15 Dex/Int Hallo Helm/l10 rhino plat pack helm/l10 Archer plat pack helm-Ordered by preference.
Crit/hit% Dmg l10 Dex Ring

I found this build to be decent enough to get a 2:1 k/d in (mostly) 1v1s. There are things you could change with your liking, such as points from hamstring into more debuff skills. Any questions I'll answer, thanks. One more thing, at this level without your damage and crit buff, you are almost required to hit the triple combo to win a lot of fights. To do so: Rabid bite-Hamstring (other skills here) When cooled down- Rabid bite- vixen kick- Hamstring.