Ok, here is an update.
Yesterday, I went out to a local group ride that stated 20 miles @ 15~20 mph
I've been to this group before so I knew that there were some strong riders and some beginners like myself.
Due to the number of people that showed up(10) and the path riding we had to do, the group separated into two and I tried my luck with the stronger group.
This group started easy but around 3 miles in they started picking up the pace and the speed was anywhere from 22~28 mph to the turn at 10 mile mark. Same thing coming back.
I was able to hang with the group but I kept failing to notice when the pace picked up until they started pulling away rapidly and would catch up to them either when they slowed down to cruising speed at around 22 mph or I push my rear and burn myself to death every push to catch up right away. Once caught up, I was okay hanging with the group; not saying it was a breeze but I was okay.
Not having the sense to see the push right away made me fall about 5 bike lengths away every time and that made the whole effort so much harder without any draft on windy trail.
Even when I caught up, I knew I spent more energy than I needed to and when the next push came, I started to fall back again only to catch up expending more energy than I needed to.
All in all, I was able to hang but then again, at a cost of a lot of unnecessary effort.
Once we were done with 20 miles, I felt I still had enough gas to go another 10~15 miles.
With that said, I think I may hold off on joining the group ride I mentioned in the OP due to the fact that I'm almost positive they will be pushing harder and longer and I've learned that I need more practice to recognize certain situations in the group ride.
Thanks for all of the advice and any more tips on group rides are also welcome!