Pudge won't budge!!!

I tried my first class at the Y about ten days ago. I'm still shuddering with fear. It was a body sculpting class and I really wanted to be in the group environment. I was quickly made aware of my naivity. This wasn't just an aerobics class, this was a butt-kicking like I haven't had in years! I couldn't finish the class because my heart rate was way too high. I shouldn't have used the weights and done the over head arm exercises. I realized this years ago when I would workout at home but didn't remember until my heart was racing. Now, I am 31 and you know what they say. As soon as the calendar says you're 30, there's no hope for you. You immediately cannot lose weight, boost your metabolism, or burn fat and you can forget about . How unfortunate for me to be so elderly. :( Give me a break people!!! Don't tell me that I can't train my body to be better just because of my number age! I may have to tweak my workouts and diet, but it can be done.