Jump in and give it a go - I too have pretty comprehensive vertigo but as mentioned above flying is a completely different prospect and doesn't bother me in the slightest.
It's nothing like sitting in a commercial aircraft. If it's a bumpy day you can get some minor "dropping sensations", on the flip side if it's a calm day, it can be smoother than a car! I find that it's one of those things though - if you're in control you don't notice it at all.
Honestly - light aircraft motion is something you become accustomed to, like any new sensation (sailing, or whatever). If you decide to take up flying, you will adapt very quickly. Trust me, it's worth it!
Pick a nice day, and go up for a flight, otherwise you'll always be wondering!