congratulations! What a wonderful plan for the future. I started my career in the fitness industry when I was 40 and had wonderful 18 years so far.
Susan’s suggestions are right on. Whatever your plans may be, you may also need to get a certification regardless of whether you have a degree in exercise science or not. Personally, I have an affiliation with a wellness center, and there such certification is required even in the presence of a degree. The stated reason is that certifying organizations mandate continued education and current CPR/AED whereas a degree does not.
I wish you good luck for the future.
A degree in business is excellent
If you can get another degree in Health Science , Kinesiology or Exercise Physiology that would be wonderful
As for certifications, I recommend Nationally Recognized Accredited ones such as ACSM, NASM, and ACE
There are many questions on this site about this very topic