About Sunday Mass attendance obligation, one must arrive before the Creed is said. Otherwise it’s not acceptable/doesn’t count and one has to attend another Mass to comply. Having said that, I think it’s fine and not disrespectful to confess before the Creed is said. Disrespectful is to arrive after the Creed, take the communion and leave before the blessing, among other things.
Personally, I like to attend Masses where confessions are heard right before Mass starts. Having to drive for two consecutive days, one to confess, the other for Mass, doesn’t give me much encouragement, especially when one is dealing with a toddler. That’s why, in my case, going to vigil Mass sounds more convenient than going on Sundays because these days, confessions are heard on Saturdays one hour before the vigil Mass. Plus, for kids that can take the communion, it’s better this way. I cannot imagine being a parent and constantly ask the child if he/she has or wants to confess his/her sins. I prefer to arrive one hour before Mass when confessions are heard, sit, and if someone has to confess without putting them on a spotlight, they are free to do so without questioning. Plus we get plenty of time to meditate.