Would you please rephrase the bold part on such a way that i could get it better? or would you rephrase the bold part in another way?

Or, ***does this phrase mean before?***

The money could be paid **as early as** next week.
He started writing music **as early as** 1980.

If the idiom as early as is the same as early, could we rephrase the following sentence with it?

Early booking is essential. as space is limited.

Or, what is the difference between these?

I wake up as early ay as 6 o'clock

I wake up at 6 o'clock

Thanks in advance