Congrats! I finished my Rescue OW last weekend as well. Definitely the most tiring, exhausting and best class out there. I am not a young pup by any stretch of the imagination and as for fitness, let's say I need to work at it. After reading the book and discussing different scenarios, I knew I was in for a long day. After the OW session, I was physically exhausted but mentally focused on everything around me. What I found amazing is the way I began looking at my surroundings.
There were 8 of us in the class. After the final scenario, 5 of the 8 left. The remaining 3 had a bite to eat and went back for another "easy" dive. Divehearts was there with a group so our mental intensity as we approached the water amazing watching these folks and making mental notes of "what might go wrong". Brought a totally new awareness of what was actually going on. After our 45 minute dive, we dragged ourselves out of the water and discussed the days activities. We were amazed at what each of us observed after the class. Future dives are going to have a whole new perspective...and it won't be the dives themselves. It will be the pre-dive, the equipment inspection, buddy checks, etc and probably most significant difference will be watching/checking the psychological mannerisms of the other divers.
I would recommend that Rescue is the minimum cert level each diver should strive towards. You will not regret it.
