Ethics question. Trying watches that you know you wont buy

I personally have window shopped at a variety of ADs but have never asked to see any watches out of fear for the sales person refusing or needing a credit check or something. I am only 22, so I feel that I am much younger than many prospective customers, however that does not mean I am not equally or even more interested than older potential customers.

I have wanted to try a few watches on to get a better feel for them and to narrow down my preferences for when I eventually do make a purchase. Do you guys have any recommendations for how to ensure the seller that I am a serious customer despite my age? Every time I have spoken to sale personnel I get an odd, almost condescending vibe because I am young.