I just won my first 1v1 against the AI on moderate, and I have a couple of questions

I bought HD+DLC on steam about two months ago, and I used to play on standard when I was a kid. The first time I tried a standard game on HD, I was totally blown out of the water by the new AI, and I was obviously super rusty.

So, I set out to get better at the game by forcing random civs on random maps, starting with standard 1v1, then adding more free-for-all players to where I could handle a 4 player free-for-all.

After feeling comfortable beating 4 player free-for-all on standard, I decided to try a few moderate 1v1 matches (again, random civs and maps) and on my third round, I beat the Byzantines while playing as the Incas (it was my first time playing as them). It was a long game, and all of the gold on the map was extinguished by the end of it. I had to change my army composition a few times in order to make a successful final push.

This milepost took me about 35 hours of game time to accomplish. I think I could keep on the same trend and eventually (maybe with 150 hrs of gameplay) defeat a random 1v1 civ on hard or hardest, but I'm worried that if I jump into online games with real humans, I'll face a similarly tough learning curve, and be cursed with bad habits from playing the AI only.

My Qs: what are the fundamentals for pivoting from playing the computer vs P2P? Are there any standard benchmarks you should meet before attempting playing online? If so, what gradual mileposts did you aim for in order to achieve those benchmarks?

Thank you, and I hope the discussion is fruitful for old players and new players alike.