Which state I should level up?

I'm level 33 and my starting class is Warrior
vit 18
att 10
end 14
str 21
dex 18
res 14
int 10
fai 12
I have Black Night sword and I don't know which stat I should level up after using it?
I want to level up faith because I think it is required for magics in future,is it right?
How about intelligence and attunement?
Dose more strength and dexterity is important now?

I don't really know where you're going with this build and I don't really like the BK Sword, IMO there are better greatswords out there.

Having said that, you can't go wrong with more Vitality and Endurance.

What is wrong about this build?

Nothing yet. The Resistance I disagree with, but that's it. The build is still "young" so it can still work out in the end, my thing is that I don't see what you want out of it.

You mentioned adding Faith and Intelligence, but to what end? What spells do you want, offensive spells, buffs, support spells? I'm not really sure.

IMO, vitality and endurance rank low on the upgrade list. Get your weapon as powerful as you can early. Much more valuable than high vitality. Once you get your weapon powerful, then pump vitality and endurance. Once you have a comfortable amount, then decide if you want another weapon (like magic) and start putting stats into that.

It's hard to build a jack of all trades character. If I were you I'd focus on either melee or magic for now.

Melee - you want strength and dexterity. Only up to around 40 each roughly, and focus more on the stat that buffs the weapon you're enjoying the most. If you really like the Black Knight Sword it scales off Strength better, but don't forsake dexterity too much - you may find another weapon later on that's more fun.

Magic - there's three kinds, sorcery, miracles, and pyromancy. Sorcery requires intelligence, miracles require faith, and pyromancy requires no specific stat. However, attunement is required for having more slots for more spells at any one time (you can swap at a bonfire).

Since you're already invested in strength mostly, I'd go with that, then dexterity, then possibly some vitality or endurance depending upon which you feel you need most. If you really want magic I'd suggest Pyromancy, but if you're still determined for others then pick one and go that way - you can make magic/enchanted or divine/occult weapons that'll get some serious buffing from strength and dex as well as intelligence or faith.