You just need to know, not remember. I know the vienna is e4 e5 Nc3 like I know 1+1=3. It's all pattern recognition. So tactics for now.
Starting learning chess after 30 - what goal to set ?

So my question is : could anyone in the same situation could reassure me, and tell me he could reach a 'good' level in chess ?
What goal could I set, eg. as 'ELO ranking' on chess.com
Hungarian master Eva Karakas played her first ranked game when she was 28. Only 4 years later she was national champion, and another years later she played in the Candidates Tournament for the world championship. Okay, it was 70 years ago, but it shows that the glass ceiling is high.
As for goals, I don't think you should set a goal of any number of Elo-points. And certainly don't call it ELO, it is not an acronym, it is named after the guy who invented it.
Your main goal should be to not play games like this:
Not defending the pawn and letting them take it for free was bad. Resigning after you lost a mere pawn is just criminal. Where is the fighting spirit?

So my question is : could anyone in the same situation could reassure me, and tell me he could reach a 'good' level in chess ?
What goal could I set, eg. as 'ELO ranking' on chess.com
Hungarian master Eva Karakas played her first ranked game when she was 28. Only 4 years later she was national champion, and another years later she played in the Candidates Tournament for the world championship. Okay, it was 70 years ago, but it shows that the glass ceiling is high.
As for goals, I don't think you should set a goal of any number of Elo-points. And certainly don't call it ELO, it is not an acronym, it is named after the guy who invented it.
Your main goal should be to not play games like this:
Not defending the pawn and letting them take it for free was bad. Resigning after you lost a mere pawn is just criminal. Where is the fighting spirit?
A pawn? Bro, that is too early. If I hang a pawn I call it a gambit and move on. If I hang a queen I call it refusing to simp and play until I'm at least 13 points down in material.

Actually I had no recollection of this game.
But there is another game that almost made me quit :
Half a dozen mating opportunity, all missed, refused a draw and getting mated myself.

If you are over 30 and still playing chess on this site your only goal must be to avoid getting checkmated in less than 19 moves as the young brilliant chess players are in abundance here

If you are over 30 and still playing chess on this site your only goal must be to avoid getting checkmated in less than 19 moves as the young brilliant chess players are in abundance here

there is another game that almost made me quit :
Half a dozen mating opportunity, all missed, refused a draw and getting mated myself.
I think that game is a good candidate to go over and try to spot all the missed opportunities. My favourite is move 15, where instead of 15. Bd3 you could have won the black queen with a tactical trick.

I think that game is a good candidate to go over and try to spot all the missed opportunities. My favourite is move 15, where instead of 15. Bd3 you could have won the black queen with a tactical trick.
yes! those ugly, painful losses are the best ones to study. When you want to bang your head against the wall and scream, "How can I be so stupid!", its time to sit down and answer that question.

you should concentrate on material chess, loan these books on archive.org
https://archive.org/details/batsfordchesscou00basm
https://archive.org/details/batsfordsecondch0000basm
@18
"my main difficulty will me memorization" ++ Strange for a lawyer
Everybody thinks lawyers have to memorize laws and stuffs. We don't.
Being a lawyer isn't like having to recite a lesson by heart. We have books, and databases and many tools for that. Strange to see that this clichee won't die across borders.