A young friend of mine went on her first cruise when she was even younger...as in too young to drink. Got to Mexico and went to a bar where nobody cared how old she and her friend were. The ship was there overnight, luckily, because they got back to the pier at 5 a.m. and neither of them could remember which ship they were on! They just went up one gangway after another until they found one that said their boarding passes were okay and let them on board. Have been teasing her about it ever since.
On the other hand, I don't believe in the other extreme either, such as needing to have every little thing nailed down in advance. I don't do the fretting over little stuff thing, especially on vacation.
To each his own. We are all individuals.