Can Muslim girl marry a hindu Brahmin boy

Laws about marriage go by country, and in most countries, it's just a minimum age, unless parents agree.

When religions are part of marriage laws, you either go by those laws or you leave the country to go to one that allows you to marry.
If parents say no, and disown you, then you make a decision based on your heart and how well you can survive financially and emotionally without them.

Have you consulted both your parents, and those of your intended? What do they say? Do they know each other and have talked together?

If the Muslims girl parents are true believers to their faith, no, they would never allow it.