Your English seems quite good, so no worries!
Rhythm must be at the forefront of one's musical imagination at all times. This is not to say that we must play in a way that is rigid, or mechanical. But if you are not aware of the rhythm, the audience will not be aware of the rhythm, and rhythm IS important!
If you wish to have a small 'breath' in between repeats, rather than 'ASAP' that is okay! Just don't make it so long that we hear it as a big pause.
Regarding ornamentation: don't feel you 'have to' ornament the piece the same way in the same place each time! Feel free to have no ornaments the first time, and put them in on the repeats. Or, you could put the ornament in one place the first time, and then in another place on the repeat.
Or, you could put the same ornament in both times, in the same place! But if you do that, try to find some subtle change, so that the same ornament means something slightly different the 2nd time. If we play the repeat exactly the same way as we played it the first time, there is definitely a small risk that it could sound stale.
Nuance!

Nuance is everything in piano playing!