CAT

Yes, you can. It would help you in a huge way if you are going to do MBA for sure once you are done with your graduation. You can apply for some coaching class for mock tests. Mock tests would help you in preparation. Or if you want you can join the classes as well. Many classes nowadays provide feature like if you are not able to get into the college that you want you can sit for their lectures in next year again. You get access to their online study material as well. As you would give the CAT exam while you are in the final year of your graduation you will get an idea about how entrance exams are in nature. Thus, even if you are not able to score in this year you stand a pretty good chance in the following year for scoring more marks as your score will improve only. So you should go for it in your final year of graduation. There is a lot free study material as well as free mock tests available online which might be useful for the preparation.

I would list out the pros and cons of various reputed and best performing online coaching institutes which would lead you to pick the best from your side.
1) Mindworkz - Best CAT prep institute in India
You would have the privilege to grab the knowledge of most recognized and reputed trainers but it is expensive.
2) Career Launcher - Coaching for CAT
Offers large amount of practice questions.
Videos are really good and understandable.
No live sessions to get your doubts clarified.
Expense would be a burden again
3) Olive Board- Online Practice & Preparation Platform
Offers mock tests series and unlimited Online Tests with 10,000+ Questions and Detailed Solutions.
4) Handa Ka Funda - Online CAT Coaching Classes - MBA 2017
750+ video tutorials
Live classes every weekend to get your doubts clarified through live chats
CAT 2017 Test Series along with solutions.
Economical
22+ Theory Books for preparation
The above mentioned players are reputed and well recognized institutes. There are a lot more players in the CAT coaching market. All the institutes mentioned above hold success and failure stories. It is up to you to pick the one of your choice.

Top Coaching Institutes In Allahabad are,
1) Career Forum
Address Of Institute:
43/4 S.P Marg, Opposite HDFC Bank, Civil Lines,
Allahabad, Uttar Pradesh.
Some Course fees of Career Forum (In Rs.)
CAT Premium- 11900
CAT Plus- 10700
Focus CAT- 7900
2) TIME Institute
Address of Institute:
14/2 A, kamala Nehru Road, Infront of Prayag Sangeet
Samiti, Besides of Civil Lines, Hanuman mandir, Civil
Lines, Allahabad, Uttar Pradesh.
3) Career Launcher
Address Of Institute:
43/33, sardar Patel Marg, Ground Floor, Civil Lines,
Allahabad, Uttar Pradesh.
4) IMS
Address of Institute:
2nd Floor, 54 Shri Ram Complex, Sardar Patel Marg,
Civil Lines, Allahabad, Uttar Pradesh.
5) Lakshya Career Institutes
Address Of Institute:
649, Old Katra, near Mishra PPharmacy, University
Chauraha, Allahabad, Uttar Pradesh.
6) Panacea CareeAddress Of Institute:
33/43, SP Marg, Civil Lines
Allahabad, Uttar Pradesh.