Is it ok to play grand theft auto with my 6 year old?

It generally depends on the game in the series & what you're doing in-game.

For me, I will NOT allow my nephews to play GTA V because of some content that I find objectionable (there's one mission in particular that makes MOST reasonable players a bit queasy & provide major content warnings when streaming that particular section of the mission).

For GTA III, I would permit with supervision.  There's nothing heavily objectionable there...  the only thing that would be restricted would be picking up prostitutes.

For GTA: Vice City, I would forbid access to the strip club (The Pole Position Club) for the adult content (in addition to pick up prostitutes)...  otherwise I would permit with supervision.

If he's only playing around the map & going general mayhem & carnage (with cheats, most likely), then I'll let him go at it as long as he knows it's just fantasy & he not allowed to do it in real life as well as there being consequences for his actions (so I wouldn't use the "Lose Want Level" cheat for him).

HOWEVER, I would give their parents the final say on if they're permitted or not (as I'll try my best to honor their wishes).  As the kid is your own, you'll have to use your best discretion...  otherwise you should be OK.

This is just my 2 KB here, but I hope this helps!

I played rated M games with my older cousin since I was 6 and I turned out fine.

I wouldn't want my kid playing it at that age

So teens stole a SUV got chased by cops crashed in neighbors front yard. I grabbed one of them pinned him down cops caught up to him and went knees to the face on a minor. GTA is a great ways to teach minors. 

RIP the mango tree 

Go by the rating on the game. They may get the idea it's OK to steal but it may give you the chance to talk with him that it's wrong to do those things in real life. It's your choice.

I don't see a problem with 18+ games on younger kids. They have to grow up anyway, it's not the game that causes violence, it's often friends (fakes) or family that cause the problems. My brother plays GTA V by himself and he is 6, been playing since he was 4 and a half. 

Would he know what to do. At 6, I don’t think he’s coordinated enough to play the game unless it’s a button smasher. The gta game can be too complex for a 6 year old. If he can’t do the job then he’ll get frustrated and that might stop him from playing video games. 

GTA was the only M-rated game that I wouldn't buy for my kids.  I told them that once you turn 17, you can buy your own copy.

Two of the three of them did exactly that.

I've let my kids play CoD games since they were 12 in addition to other M-rated games that I didn't have issues with.

It was just GTA where I put that limitation down on them.

Why don’t you get a newer system I hear the ps5 is coming out soon. 

Yes! he will learn to disrespect women, and hit the strip club and jerk off! PogChampion, and will slaughter all the hookers after he pays them for intercourse