I really enjoy exercising and physical fitness.  Do you work out?
I do work out! And it helps me feel great through proper nutrition, moderate-vigorous physical exercise, and sufficient rest.
How often should I work out?
You should work out quite often, but not every day - it'll boost the immune system and helps prevent things sush as  as coronary heart disease, type 2 diabetes, and obesity.
That is definitely a plus.  Why should I not work out every day?  Would it be bad for me?
You don't want to over work your muscles.  And being fit is the quality or state of being fit.
Yeah, I wouldn't want to overwork myself.  I do want to be fit and prevent disease and getting overweight.  Is it better to do cardio or weights?
Strength training is good - can provide significant functional benefits and improvement in overall health and well-being as well as  improved cardiac function!