I play chess somewhat regularly, against my son (8). So far he can't really threaten me, but he will, in a year or two.
I never got "into it" to the point where I started memorizing anything, though. My life is plenty busy without that.
And any online chess playing will be dominated by those few who have a chess program running in the other window, and you'll always wonder if your opponent is one of those few, which really spoils it. I'll pass on that, thank you.
The only complications are with castling (which isn't hard to follow - king moves one square towards castle and castle jumps over it, but this must be their first involvement in the game, there must be no other piece between them, and you can't castle to get out of check)...
None of the fields the king moves through may be threatened, either.
...a pawn which has just moved two squares forward can be taken by a pawn it lands next to just as if it had only moved one square forward instead of two...En passant.
A rule that even Grand Masters have stumbled over, one of them recently.