Which one of the two sentences is correct ?

They are both OK provided the phrase "to hit the bed" is correct.

And they mean different things.

To me,
21:00 or 22:00 is early whereas 23:49 is quite late.

You can say you'll go to bed soon at 21:00 and at 23:00 and even at 1:30.

Soon means after a short period of time (counting from now)

Early means long before the night comes (in your context).
(Prior to the usual or arranged time — Heinemann dict.)

P.S.: Don't know how to put it better.
P.P.S.: I know the expression "to hit the bottle" but I am not sure as to "to hit the bed".

Also, "hit the hay."

I was so surprised by that, that I looked too.

Hit the bed of the truck
Hit the bed frame
Something that was thrown hit the bed
In other words, things that literally struck the bed or even the truck bed. Only one had "hit the bed" in the sense of "go to bed" and it was a play on the phrase "hit the town."

I'd like to hear from native English speakers who actually use this phrase to mean "go to bed," not quotes from online blogs, etc.

Grammar Geek wrote:

I was so surprised by that, that I looked too. Hit the bed of the truck Hit the bed frame Something that was thrown hit the bed In other words, things that literally struck the bed or even the truck bed. Only one had "hit the bed" in the sense of "go to bed" and it was a play on the phrase "hit the town." I'd like to hear from native English speakers who actually use this phrase to mean "go to bed," not quotes from online blogs, etc.

What about this?