Congratulations to you and your son for his acceptance into the fire academy!!
Since you are trying to lose weight, I would recommend doing a mixture of cardio & strength through a hybrid. It's really important as women to lift weights, and I am guessing you have the equipment since you and your son have been doing P90X.

How long do you have each day to workout? Jenelle sent me and the other people in our accountability group her hybrid of TurboFire and ChaLEAN Extreme; IT'S GREAT. She felt the same way with some of the shorter HIITs too, and she added strength or core workouts to those days. Each day is about 60-70 minutes which is close to P90X. Would you like me to send you the hybrid? I also have one that combines Insanity, TurboFire, and ChaLEAN if you'd like an even bigger variety since you are having a hard time choosing.
Also, I know how hard it can be when you lose your accountability partner. When I graduated college, I lost my workout buddy and was not as motivated. I started a free Facebook group last year though and it's made a huge difference! Most of us are women 25-60 working out and dieting. We share meal plans, hybrids, workouts, tips, progress, before and after shots, and also do a monthly challenge and giveaway to whoever is crushing their goals. It's a lot of fun and has definitely helped me. Would you like me to add you to it? My facebook is facebook.com/kaleesorey. It's private as well so no one else will see or know you are in the group.

Can't wait to hear what workout you pick!
Kalee