Open Question: Advice on rest between workouts?

Ok well currently my routine is this Monday & Thursday -Chest/Triceps Tuesday & Saturday- Legs Wednesday & Sunday- Biceps/Back Friday- Abs/Cardio I just recently joined Golds Gym. I use to work out at my house but it wasnt doin the job anymore. The first time ever working out at Golds it was a leg day and my legs were killin me the next day. They are still a little sore now but its another leg day tomorrow. Im pretty sure my legs were so sore because im not use to all the different machines and ways to work them. After a week or so i shouldnt be AS sore from my workouts i would think. So is it ok if i just work my legs out at like 75% tomorrow. I wouldnnt be straining them too much since they are still a little sore but I would still be working them. I have about 3 full days of rest between each workout of the same group of muscles. I try to get ATLEAST 100g of protein a day just from shakes/bars not including other foods such as eggs/meats. With this amount of protein combined with enough sleep i believe 72 hours of rest is sufficient. Any advice?