Has anyone had their child start at community college because you didn't think they were mature enough to leave home at 18? If so, how did things work out for your child?
Hmm, I think it can be a good idea of the 18 year old thinks they're not ready to leave home. If they did everything they needed to do to get admitted to a four-year school and want to go, then they should determine whether they go even if a parent thinks maybe they're not ready. Don't base a determination on how your current HS senior is behaving.
Every kid is different though. We don't know your situation. Some people on DCUM would call their kid immature if they don't keep their bedroom neat and tidy, organize everything in a planner, and follow a disciplined exercise routine.
My DC had a very bumpy road through HS (to put it lightly), I had my doubts about sending her - she had absolutely no issues with being 1000+ miles away.