Is it normal for parents, both mother and father, above 50 to have a night picnic with their children of 19 and 24 in public ground? Am I right to hesitate going with them?

I know adult children feel awkward going with their senior parents especially to the places where youths gather in crowds. Still sometimes they are compelled to do so. I myself very rarely see adults with their parents in a vehicle. Still I had doubts..