I am on level 13, i think. My character is level 19, rogue, using a bow

base (now)

Str 33 (35
Magic 22 (41)
DEX 95 (97)
VIT 28 (30)

LIFE 92
MANA 79

AC 50
to hit 98%
damage 13-22

all resistances at zero

Is it good?

certainly better than your spelling ;)

Your armor class is much too low to avoid being hit in melee, so you will need to keep your distance from enemies. Your damage is too low to stun enemies consistently, and for some enemies, to stun them at all. That means you will need to keep moving to keep your distance, rather than holding them off by stunning them as they advance.

Resistances at 0% will be painful as you go deeper. On level 16, you will face Advocates, which cast Fireball. You're likely, but not guaranteed, to face other forms of magical attack along the way. With resistances equal to 0%, you can be stunned by magical attacks that deal sufficient damage.

You might be able to finish the game as is, but you will need to be clever about it. A much stronger character could play sloppily and win through brute strength. Yours cannot. Minimize the number of enemies you face at once. Use terrain to mitigate their ability to attack you. Be prepared to heal yourself frequently. Be prepared to retreat into cleared areas, and lead the enemy on a chase.

the comment above mine states you wont be able to effectively stun enemies with such damage. i completely agree. stun mechanics is extremely important for rogue. in hell you need damage that exceeds 30 on lower end, and 35 on higher end. this will make big difference. stun threshold is simple in diablo. monsterlevel + 3

this means if a knight in hell has monster.level 30, you will always stun them with 33 damage. and if your damage is 24-33, then you will stun them with 10% of your hits. take it up to 29-38 amd you stun them 60% of the time. (damage of 29, 30, 31, 32 does not stun. 33, 34, 35, 36, 37, and 38 - does). and if you can raise the damage further to 33-42, all of your hits will stun the target and it will not be able to move.

What stats should i be investing in, then? I am lvl 21 now, i spent the additional 10 pointa in dex and str 5 apiece

According to Jarulf's Guide, section 2.2.2 Damage done, a rogue with a bow has character damage (Str + Dex) * clvl / 200, so your choice was a good one. Ideally, you want a minimum damage of 33. At your current level, that would require the sum of strength and dexterity to be at least 315. This is probably not attainable in single player, at least not without starting a new dungeon. If you have found any bows with a +damage modifier, that would help. What kind of bow are you using? Do you have any other bows, with better base damage? Do you have any items with +resistance modifiers?

If your rogue's damage had been high enough to stun lock The Dark Lord, you would not have needed that many health potions.

Do you think i was underleveled because i couldn't be bothered to clear out every single level? I restarted once when i was level 7 (in the cathedral, i mean) but that was it

Skipping monsters will cost you some experience, but whether that was enough to leave you underleveled, I cannot say. I play mostly multiplayer, which has different rules, and tends to encourage skipping some areas and replaying others, which further skews the expected character level.

A crude calculation from Jarulf's Guide would suggest you were extremely underleveled, so I am inclined not to trust that calculation. Each dungeon level can hold, at capacity, ~200 monsters. If we assume that each level is closer to 180, to allow that you might miss a few, and that not every level will be packed full, then by the start of dungeon level 13, you should have killed ~2160 monsters and, according to that crude calculation based on the experience table in section 2.6, you would be level ~27. This seems much too high, so I think the Guide's warning that "This is in practice impossible and even theoretically impossible at low levels." is even more important than it might appear.

Reaching level 21 seems much more reasonable, particularly since level 20 would allow you to enter Nightmare difficulty (if you were in multiplayer).