DH got his paralegal certificate before he went to law school. He wanted to work in the field for a couple of years before committing to law school. That was after he had his four year degree. In our area, the Pacific Northwest, paralegal certificate holders tend to have an associate's degree with their certificate. There's lots of online info about salary ranges in various areas of the country. I wouldn't want to scare you with the salary ranges around here as the average annual income is about $36K in our county. When I started practising as an attorney 17 years ago my starting pay was $24K a year -- it was a recession I was happy to get it.
A good paralegal who can think and juggle without making mistakes is worth their weight in gold. When a paralegal screws up they lose their job but their attorney loses their house! If you can reliably get your work done and do your fair share of billing, you will never have to worry about your job if you are in a private practice situation. Governmental agencies may be a bit different.
Do you know any attorneys or people who work in law offices? They might be willing to talk to you. Or they may have some orientation program for people entering a paralegal program. I just did a program at my old law school for incoming law students -- it gives them a chance to speak with an attorney and start understanding what is involved.
Oh, and learn everything that you can about word processing, docketing systems, timekeeping, Outlook and all the various ethical pitfalls that can wreak havoc.
That may have been TMI but we lawyers tend to be a bit wordy! Good luck!