You should opt for architecture only if your interest lies in this field. It shouldn’t be a backup option for you. This is because the field involves Arts, Science, Maths, and Humanities, all together. You’ll do well in this field only if you like architecture.
As far as MNIT Jaipur is concerned, it isn’t the best place for architectural studies. They’ll offer you limited practical exposure, and the curriculum hasn’t been updated for long. The infrastructure of this department is pretty average, they don’t organize any educational trips, and only a few faculty members are good.
I wouldn’t recommend MNIT for your B.Arch. Instead, try to look for some better alternatives.