Hi Talat,
I think a shared-business hosting won't do the trick, as 100 concurrent users could be a mess at times. I would recommend you to go to a cloud hosting like Google or Amazon, or if you cannot manage it yourself.
Have someone like cloudways take control of your Moodle App, they are good with support and also you can always scale up and scale down your server needs, from small server (25-40 users) to a large or x-x-large server (2000 students) within minutes.