Mazel Tov!!
There’s hundreds of aspects to your question.
Here a small point on this issue:
Keep your mouth shut when the young couple does something stupid/irresponsible/immature. This includes not talking to your daughter behind her husbands back – not even a small comment or ‘suggestion’ This can undermine there marriage and put your daughter in a difficult position.
(I’m obviously refering to minor things and not if you have see real red flats that are of concern to your daughters well being..)