Hi, I saw your post and wondered if you've spoken to your GP about your abdominal symptoms? It may be that they can refer you for further investigations if needs be, and if the referral was a gynae one they may well do a smear test if they felt it appropriate. There are lots of conditions that can cause this type of symptom, most of them wouldn't be serious.
I know the screening of under 25s is an ongoing debate. Statiscally CC is rare in the under 25s whereas cell changes that would return to normal are very common, so I can understand why the age is 25 (the anxiety associated with cell changes is no joke) but I also understand the concerns of women under that age. I think being aware of symptoms is important, and if you're concerned in any way push to get them checked.
If after investiagtion/consultation they don't feel a smear is appropriate there's always the option of a private smear if this is the only outcome that will put your mind at rest. You can get basic options (just a smear) or for a bit more money you can also get your smear tested for HPV.
As an aside, I did have my first smear at 21 but can't remember how that happened, and whether the age used to be lower or if my surgery was proactive in getting young women checked. My first smear was normal, but I've suffered a lot with gynae problems throughout my life which were investiagted, and which I do not believe are related my current situation.
I'm not sure if this helps at all, I just wanted to encourage you to see your GP about your abdominal symptoms.
Wishing you all the best, take care x