I was born in Uttar Pradesh and now I am studying in maharashtra so to which sttate do I belong??
For most of the state, the eligibility for being a domicile is that the person must reside in the state for a minimum time period of 10 years. Now as you are studying there and if you are passing your 10 & 12 from Maharastra then also in some examination you can apply for the state quota of Maharastra. In general sense, you can apply for being an domicile if you reside for a minimum of 10 years.
I hope this answer helps. All the very best for your future endeavors!