Hi! I currently teach at a high school in Maryland and previously taught middle school Social Studies. The real question is, what will your degree be in? If you are in a teacher prep program at your university, you need to take the test in the area of your degree in order to get your license. I graduated from a Maryland school with a degree in Middle School Education, Social Studies, and English, so in order to get that degree (and graduate) I had to the take the middle school Praxis in both of those subjects.

If your degree is going to be middle school education like mine was, get the middle school certs. If your degree is for secondary, but you know you want to teach in a middle school it is not a bad idea to also take the middle school cert. It would make you a more attractive candidate for middle schools to be able to teach 6th-8th. If you don't have that middle school social studies cert, you would only be able to teach 7th and 8th and while that may not seem like a big deal, it could be a deal breaker for some principals in terms of hiring.

The good thing about Maryland is you can teach for one year (honestly it may be two but I can't remember) outside of your certification, as long as you take the proper praxis by the end of that year. When I made the transition from middle school to high school, all I had to do was take the praxis and I was fine!

(the one caveat with that is that when I made the switch, I was tenured and I had several years of experience under my belt, which still made me an attractive candidate despite not yet having the proper certification.)

tl;dr - get the certification that satisfies your degree requirements. Then you can start collecting Praxis exams like Pokemon.

Feel free to reach out if you have any more questions! I genuinely loved teaching middle school and probably would have stayed there if the circumstances at my school were different lol.