In other words, if your boyfriend cannot be naturalized in the United States within 3-4 years,
It will take about three years to apply for change of identity and green card.
Before you arrive, you must keep a legal status alone, such as continuing your studies.
You can't work.
Marrying a green card is different from marrying a citizen. You can't apply for adjusting your identity immediately, that is, you can't apply for a green card immediately.
Can't wait until the schedule is up.