M.Sc Maths

Yes Vamsi,
There is no reason why you can't. But, also you must have relevant education background, have good grades, LOR, SOP etc.

First of all, set priorities to the things you want to do. Then, you may do the first two things in parallel. All the best for your future.

Here is a list of the best M.Sc Colleges in Bangalore:
Indian Institute of Science
International Institute of Information Technology
Jain University
Jyoti Nivas College Autonomous
Christ (Deemed to be University)
Mount Carmel College
MS Ramaiah College of Arts Science & Commerce
Reva Institute of Science
St. Josephs College
The National Degree College

Following topics are included for BHU PET M.Sc. Maths syllabus-
Fractions & Decimals, Ratio & Proportion, Square Roots
Simple & Compound Interest
Time & Speed, Unitary Method, Time & Work
Profit & Loss
Percentage & Discount
Simple Equations
Quadratic Equations
Polynomials
Exponents
Functions
Sets
Venn Diagrams
Relations
Functions
Triangles
Properties of Circles
Mean
Median
Mode
Probability
Permutation and Combinations

Hi Shree,
Please refer this link to get an insight about the syllabus for BHU PET 2019. This link also provides registration details, fee mode, important dates and other details. I hope this will help you prepare for the best. https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.shiksha.com/university/bhu-banaras-hindu-university/amp/bhu-pet-exam&ved=2ahUKEwjGquCrqdTgAhUUbysKHapeDtMQFjAKegQIAhAB&usg=AOvVaw2Zex-xbN00BPqFd6r6CPPv&cf=1.

AUCET 2019 is scheduled to be conducted in the second week of May 2019. AUCET entrance test is conducted through the offline mode i.e. it is a Paper-Pen Based Test.

Hi Manisha,
It's really good to see your enthusiasm. Yes you can do and always seek for knowledge. There is no age limit to do anything. Keep it up.
All the best Manisha.

No, you need to have done B.Sc mathematics in order to be eligible.

Hi!
You can refer https://www.shiksha.com/science/articles/top-10-bsc-msc-colleges-in-india-blogId-13473
For scholarship details, you need to contact the college directly to know their schemes.