Three years. Similar situation as yours - got a horse that was beyond my comfort zone. Took me a long time to find a trainer that "got" my horse and could deal with my nervousness, but now that I have we are making great strides. You will too.
Wintec and Ovation both make very good synthetic shaped dressage girths with elastic at both ends. I have the Ovation Chafeless, have had it for years and it's held up very well.