Just did the same thing starting last Sunday - first gym effort since getting out of the Army back in 1990. I let myself go to pot, and decided to diet to lose weight; hit a plateau after 20 pounds. So, I figured I needed to add in exercise...
First session was focused on chest and arms - I have to admit I way overdid it on that one and am still VERY sort in my upper arms three days after.
Session 2 I did legs on Monday - legs are sore, but not unmanageable and are already getting better. Session 3 is Wednesday (back and biceps) and then back to arms and chest Friday - Lord I hope my arms are recovered from the FIRST session by then!
Then I will shift to a normal M-W-F for weight sessions, and 3 miles on treadmill W-T-W-T-F. Saturday and Sunday will be off days I think. I sure hope for some success (and expect to get some success). I also hope to survive the experience!