Microbiology is fascinating, as the field is changing very fast especially in the area of human microbiome.
If it's in your heart to pursue the field, why not?
However, grad school is more than a full-time commitment. You really have to interview the instructors you will closely work with. I'd do a lot of digging into which school would be a great match. And find instructors who are into the areas of research you'd be into. Also, evaluate their teaching styles. Some department chairs can be very... lets just say, academia isn't always fair so you'll have to size these people up really fast, and see if you'd feel comfortable working with them, and don't go by what's presented on the surface, because in my experience, a program can say that they're about one thing and they're really not. Choose a program that has the type of reputation you'd gladly want to say you graduated from (not for the purpose of status and image), but because you truly paid for what you learned, and received the support you required. Some teachers don't always teach once they're tenured, and in fact, will use their graduate students' research for their own personal gain and benefits. There's a few corrupt (Narcissistic) ones out there. But, there are also great ones. Navigate and find your best match!
