I completely relate. My first several group rides were on the tandem with Dh, so I was "lookin' good"! (He's very strong, so it makes me look faster than I am!) The first time I tried a group ride on my own I was late getting there and most people had left, so I technically ended up riding by myself, as I feared would be the case even if I had had a head start. Then a ladies' group cropped up, so I tried that. Surprisingly, I was one of the faster one's, which made me feel good! (From the sound of it, I'm about your level, by the way.) That group was definitely more for beginners and, apparently, I was past that point.

The club's schedule conflicts a lot with mine, so it was difficult for me to ever really do a club ride, plus my fear of being the slowest made me not try too hard to make it happen. However, last Saturday, Dh offered to take the kids to their weekly horse lesson so I could do the club ride. I was nervous, like you, how it would go. This was guys and girls mixed. Turned out to be AWESOME!!! The group I rode with was right at my level. There is a 23 and 33 mile ride on Saturdays. The 33 mile ride is the "fast" group and the 23 mile ride is, apparently, the "moderate" group. They stopped at the top of all the climbs to regroup and I was thrilled to not ever be the last one. I was about in the middle, or a little behind the middle on the climbs, but pretty much in or near the front on the flat or downhill.

So, I say, jump in and try it. You might be surprised. If it doesn't work out, then at least you know what level you need to be to try it again. I do recommend trying the ladies' ride first. Much more likely to be a good first experience, but one of the shorter guy/girl rides might be fine as well. You also might want to try that 3 hill climb without the club to get an idea what it's like before trying it with them.

I say go for it.