Early pregnancy exercise when you wernt " in shape" before your bfp?

Does anyone have any suggestions as to what kind of exercise is safe for early pregnancy? I've never been "fit" really but I'd like to have a healthy pregnancy. I've read a few articles about safe exercise for early pregnancy but most of them are for women who had a work out routine before they got pregnant. I know I can't jump into a full 3 hour a day cardio routine or anything too intense but I'd like to start working out to get healthy for my new "passenger" After all this baby needs a healthy mom during the next 9 months - 25 years. I'm only 4 w 2d and I'm hopeful for a full term healthy pregnancy, I'm 30 yr old and have a six year old who would like to be apart of everything I do. Any ideas?