Once you turn 18 you should open an account in your own name and transfer the assets there. Currently your mom is the one responsible as far as the IRS cares with respect to taxes as it is her name on the account. The taxes due will be based on your mom's tax rate. As a good child you can reimburse your mom for the taxes that she has to on your behalf.
Also legally that money currently belongs to her. Any legal judgement against your mom can claim that money and it is not available for using as an asset by you on credit applications and such.
A better solution would have been for your mom to open a custodial account in your name. This way the money is still yours (you just don't have control of it until you turn 18). While probably not an issue here, the transferring of money between you and your mom (and then back) is considered a gift by the IRS. If the account was very well funded then you could run into having to deal with the annual gift limit and lifetime gift exclusion.
Based on the clarification that the question is in reference to India: while I don't know the particulars of the law in India my advice of transferring the assets when you turn 18 still remains. The main difference that I would see been India and the US would be the gift tax / exclusions. Unless someone else knows otherwise I would still expect the law in India to see the current account as being the property of the mother.