Re: What do you wish you had known before buying your first boat?
Buy a sound boat, ignoring how "pretty" she looks inside. Given your budget, you don't expect a perfect boat but spend the right amount of time checking out the important things that could end up ending your fun pretty quickly. Overall regularly maintained? Any rot detected? Loose stanchions? Bulkheads sound? You've no doubt had access to the before your purchase lists but I can't emphasize enough to spend the time checking out the right things. And, have a realistic understanding of the associated costs of boat ownership.
In the end, if you're smart, it's the most amazing hobby-have fun!
Folie a Deux