First time anal masturbation? Help?

Hello, so today I've tried to masturbate anally for the first time, I thoroughly cleaned myself down there, had lube and a condom but used a persian cucumber (lol, couldn't find anything better). Of course I made it a bit thinner before. So I opened myself a bit with my fingers before inserting, of course, everything went well and then I got a far bit of the cucumber inside me. I relaxed and could handle the pain but after a while I tried to find my prostate (first with my fingers). I think I found it but... I felt only light warm "tickling"? Nothing too pleasurable... I actually felt pain (as I expected though) when I tried to push deeper, but couldn't handle it. I felt the pain coming slowly toward my crotch... but maybe I didn't find my sweet spot. I know it's supposed to feel good, and honestly the idea of being the bottom arouses me a lot but this wasn't very pleasurable... Does it start to feel great with a partner? Did I do something wrong? I kind of feel guilty of not finding it pleasurable since the person I love and want to lose my virginity with is a top and I'm scared I won't like it (what a dumb reason to feel guilty lol). I did read stuff on this topic on the internet... I'm seventeen btw.