Hello.

 You can definitely become a pilot after graduating with a degree in aeronautical engineering. But, I will give you my opinions on it. In the end, do whatever you feel is right. Now doing aeronautical engineering before pilot training has its own pros and cons. Let me start with the pros first.

Pros : First of all, you'll have a degree as a back up and have a strong resume for your job application. If god forbid, something bad happens in your flying career and you're grounded, you'll atleast have a degree to fall back on. Next benefit is that you'll have knowledge about the design and system of aircrafts which will help you in your flight training. Also, basically in India especially, if any of those neighbour asks “Have you done engineering?” you can say “YES” because otherwise they think that you are not even a human being.

Cons : Coming to the cons now, the course will easily take approx 4 years to complete full time before you can move on to flight training (if by then flying is still your passion). It will cost you additional money to do before you again spend a huge sum for your flight training. Generally the interviews at the airline will not care if you have a degree or not because what matters to them on how you performed in your training and are you capable of becoming a valuable addition to their company or not. People may have different views on this point. As I said, these are my own opinions.

Now it's upto you to decide what you want to do because it's your life. Even if you want to stick with engineering and progress in that, it's still a really nice career but if you have that aviation and flying bug in you, consider flying training. 

Hope this is helpful.

Good luck.