Hi! Not Indian, but have a lot of desi and SE Asian friends… which doesn’t exactly qualify me to give solid advice about the cultural elements at play, but if you’re anything like my friends, I understand there are many parts of your personal life you keep private from your parents.
I don’t think announcing that you have a boyfriend warrants a sit-down conversation and in any case, assume you are away at school. If this were me, I’d slip it in during a phone call and not make it a big deal. Mention your plans together that weekend and make it clear that it’s a date. If they have questions at that point, they can ask.