It depends what your original degree is in. I am 30, and graduated from Texas A&M in 2010 with a construction management degree. I worked in it for 7 years before deciding to go back. BUT, when I did go back, I went pedal to the metal taking hard science classes at a university with a good reputation for the sciences. I have been in full time school since the beginning of 2018. I did get accepted and will be attending UT School of Dentistry in Houston this August, but I firmly believe that without going back to school and showing them a year of good grades in hard classes and going above and beyond the listed "prerequisites", I never would have had a chance at getting in. I scored well on the DAT (1.5 above their average accepted student) and have a 4.0 in the 33 hours I have taken since going back to school, and I still believe I barely got in by the skin on my teeth (Feb 4 acceptance). Even if your original degree is science-related, taking at least part time classes is important to show them you can still cut it academically since you have been out of school for a few years. Here in Texas, the schools always tell you NOT to just get a dental assistant job. You can do it part time, but they want you to be academically involved as well, even if you already have a science degree.