Did I do the right thing?

You have the right to do with your body what you wish. That includes timing when you want to grant someone the privilege to kiss you romantically.

If this guy is unsettling when he doesn't get his way after the first date, I would consider it to be a massive red flag.

If it felt too soon to you, then it was too soon. If the guy cares for you at all, he will understand. If he gets ticked off about it, then he does not care enough for you and your feelings to be worth your time.

Let's face it, a first date is useful as a way for a potential couple to find out about each other as a potential dating partner. You sure found out about him.

It shouldn't be a big deal and he shouldn't sulk if it were a perfect world. However, depending on what's going and how the rejection was spoken, could make a difference. If you made it clear that you weren't rejecting him but you just felt it was a bit too soon for you (meaning on the first date) then it should be accepted with grace.

Wishing you good luck. Stop by again.

'I explained to him how bad I want to kiss him but it felt too soon for me.."

What the heck is THAT all about?

Cripes lady - don't say no, but mean yes. Men hate that.

No wonder his mood changed.

There is no right or wrong, choice has been made. You acted against Yourself as You said it that You wanted it but felt like it is too soon. Why is it too soon, because people judge, they always will, don't try to please people or follow some "date rules". It happened I would not retrospect.
On the other hand if we shift our focus to the man, maybe he did not want show that his mood has changed but it happened, emotions - mysterious creatures. Maybe he is on a different forum blaming himself for what he did, You never know. For things to work out for people, they have to accept differences not necessarily tolerate them, at least try to understand.
In Your case whatever we tell You we are not in his head, no matter how hard we try to decipher the circumstances, no matter how many things point to one explanation, the reality might be totally different.
Take it easy, and don't overthink Your actions, You don't want someone liking Your, because You tried to please him. Trust Yourself, communicate, explain.
Allow Yourself, to just be and even making mistakes on the way.
Don't blame Yourself if something goes wrong, things happen with or without our help.
Just and advice, even if only one word is useful for You, then happy days.

people are right here. If it's too soon for you, it is OK to feel it that way.

If his mood changed, it might have meant million things, so no red flag, just wait and see what he will be next. Everything is OK as long as you feel comfortable and don't let random internet trolls to mingle into your intimate life