I was diagnosed at 27, but that was a long time ago! I'm sure there are quite a few who are around your age who are fairly newly diagnosed,
Someone came up with a theory that mid-to late 20's seem prone to T1D something to do with it being a stressful time of life and wearing yourself out more than most - you're leaving the fun care-free party life style of late teens/early 20's for serious relationships, leaving the nest, house buying, starting family, working all hours, partying all the rest!