I am a total noob to this program and RPG dev.
I teach Engilsh in universities in Japan. Many of my students like RPGs so I wanna make one RPG in easy English as a teaching aid.
A PBBG would b my 1st choice cuz I often teach in the computer room so it would b very cool to say "Today students, please play my RPG!"
I need my students to be able to access the RPG from the PC room in the university.
Is UNITY a suitable program for me?
It depends on how much work you want to put in it. Can you make a browser based game with unity, that was persistent? Yes indeed. But you'll need to code the persistence and RPG part. Expect a 3-6 month timeframe if you are working fulltime and know what you are doing, and have some cash to buy a bunch of premade assets. Scale up from there. You may want to look at BigWorld as well, but then you'll spend quite a bit more cash.
You should not build a RPG for ESL, it requires a lot of efforts. Like you need to have models, textures, 2D arts, sounds and good scripting skills to put it together. You could try to do a puzzle game instead.