7 x 5 is a very respectable size. Your perception may be “skinny”, but a 5” girth is not skinny.
Girth gains depend on the individual, as do all aspects of PE. I, for instance, had exceptional girth gains, but virtually no length gains. I only re-gained lost length, but had no “new” growth.
I jelqed three days per week, 15-20 minutes per session, 40-70% erection level, pre-warm, post warm, wet jelq with some ballooning and bends every 3 minutes or so. I gained over an inch of girth in roughly a years time or so. It can be done.
I was not terribly consistent either, but I consider myself an exception in that regard and not the rule! Consistency, good recovery (rest) time and patience is what will lead you to girth. I went from 4.125” to 5.25” and have not actively PE’d in years and I am still 5.25” girth. Good luck!