The basics
Changing from B-2 visitor to F-1 student
If you entered as a B-2 visitor and were accepted by a SEVP-certified school, you can ask USCIS to change your status to F-1 student with Form I-539, instead of going home for a visa. The school issues you a Form I-20; you pay the I-901 SEVIS fee; and you must keep valid B-2 status while the case is pending (the "bridge"). USCIS looks closely at whether you were a genuine visitor first. This is a more complex path — the assistant will guide each piece.
What if…
Can I start classes while my case is pending?
Whether and when you may begin studying depends on USCIS rules and your specific situation, and getting it wrong can affect status — so this is a legal-judgment question. Do not rely on a general answer: confirm with a licensed immigration attorney or your school’s designated school official (DSO).
Official sources
This is general information, not legal advice.