I was very lucky with my early RV experience. Shortly after I took early retirement (at 57), we bought an older Class C to "try the lifestyle", to find we loved the lifestyle but not that turkey RV. We sold it after less than a season.
About then I was tiring of the retiree life and went to work for our county transit agency and did two years driving buses. After many hours horsing 40-footers through city rush hour traffic, our 32' Georgetown Class A was no problem.
If things don't improve for you, I'd suggest asking our local transit authority or school district if any of their drivers could help you get more confident. If 60-year old grandmothers can drive a 40' bus with about 60 screaming kids on board, they ought to be a source of help.