If you are quite a few years out of college and don’t have ACT or SAT scores then schools may ask you to do a placement test such as the Compass test. I returned to school much older than 26 and as I did not complete school in the US and had no diploma to prove I had ever been to school in my home country I had to take the GED, and then take a test called the Compass test to see what level of work i was ready for. I tested into regular level classes except for math where I had to do a remedial math class to get me up to speed as it was a loooong time since I had done Algebra (I have since completed several college level math classes).
As for what sort of school, that depends on what you are ready for and what you want. I did go the community college route which worked well for me as having been out of school for so long it was a gentler start than a larger school might have been (I have a 4.0 and am in my last semester) plus I need a school within reasonable driving distance from my home. Also if you do need any remedial classes the CC route may be better for you. The other thing to think about is the cost and FA situation. If you have been working your EFC might be higher than you expect the 1st year and FA might be less than you hope for and CC might be more affordable for you. Age is not a factor for federal aid - I was eligible for financial aid and the only factor my age had was that I am, of course, an independent student and did not have to report my parent’s income.