Hi Iqbal, yes I can confirm you this has been done previously, but inserting an usb wifi dongle.
Not aware of hotspots done with the integrated wifi in the latest Raspberry versions. It should work the same, the number of possible clients connecting will depend on the capabilities.
According to https://raspberrypi.stackexchange.com/questions/50162/maximum-wi-fi-clients-on-pi-3-hotspot up to 22 students could connect if you don’t setup passwords nor encryptions in the wifi setup. It will also depend on the kind of traffic used. Just browsing will require less bandwidth and cpu power than streaming video content.
This could be helpful for you too: Kolibri toolkit at https://learningequality.org/documentation/
Regards
José L.