CBSE 12th

You can do Masters in psychology being a B.Tech CSE graduate. It's quite easier to switch now to Masters psychology. Get ready to do hardwork since you are not a psychology background student. Few colleges won't allow non psychology background students, check before and join accordingly!
Without a bachelor's degree in psychology, you can pursue an MA or MSc in psychology. The eligibility requirements will differ from one university to the other. Many leading colleges provide an MA in Psychology to graduates with a 50 percent graduation rate. So, if you have a B.Tech with a grade point average of greater than 50%, you can apply.
Some colleges grant admission to courses based on their degree grades, while others grant admission based on their entrance exam rank. In addition to the written test, some universities will conduct an oral examination. Almost all major institutions offer this subject, which you may research on the university's website.

Hello Dumadiya! As you said that you completed your 12th standard in PCB, ( I. e; without mathematics) and preferring IT in Btech. The chances are less you get a admission.
But few institutes provide this opportunity by clearing their institute test which includes mathematics also. For example, LPU is providing LPU NEST entrance test, based on your marks and eligible criteria you will provided seat in respective branches.
On the other hand you are eligible for only few btech branches in some particular colleges. You are not allowed to join in NITs and IITs with PCB background because you are not allowed to give the JEE Mains and Advanced tests.
You will be eligible to do biotechnology in btech with PCB background in almost all the government institutions except NITs and IITs.
VIT Vellore, LPU Phagwara, SRM Chennai ,MIT Manipal, etc. are some of the best engineering colleges which are allowing PCB students in India.
Do proper research about the college and the courses it is providing and prepare for their tests and try to score best to join the branch you are preferring.

You are not eligible to apply for JEE 2023 because your last chance for appearing JEE is in 2020 since you have completed your 12th in 2018.
It doesn't matter whether you have written JEE in 2018,2019,2020 , you are not allowed to write your JEE in 2023. An individual can appear for JEE for three consecutive years after completion of 12th beginning from the year of 12th completion.
For detailed information go through the JEE eligible criteria data in its website.
There is no age limit for appearing the JEE exam, but you cannot write it after the three years of completion of your 12th board.
So better to try some other competitive exams and plan your career.
Try not to sit and worry about the gone oppurtunity , so rather work hard and test your career in some other field.
All the best!!

You are not eligible for JEE 2022. Because 2021 is your year of last attempt.
You are not eligible to apply for JEE 2022 because your last chance for appearing JEE is in 2021 since you have completed your 12th in 2019.
It doesn't matter whether you have written JEE in 2019,2020,2021 , you are not allowed to write your JEE in 2022. An individual can appear for JEE for three consecutive years after completion of 12th beginning from the year of 12th completion.
For detailed information go through the JEE eligible criteria data in its website.
There is no age limit for appearing the JEE exam, but you cannot write it after the three years of completion of your 12th board.
So better to try some other competitive exams and plan your career.
Try not to sit and worry about the gone oppurtunity , so rather work hard and test your career in some other field.
All the best!!

Hi. Bachelor of Computer Application BCA is a 3-year undergraduate course that imparts knowledge on the basics of computer application and software development. BCA subjects include database management systems, software engineering, operating systems, web technology, and computer languages such as HTML, C, C+, and Java. BCA Admission 2022 is granted through both merit-based and entrance exam-based admission processes. The minimum BCA eligibility criteria followed across all Top BCA Colleges is 50% marks in 10+2 or equivalent examination with computer application/computer science as an additional or core subject. BCA Course Fees range between INR 80,000 to INR 3,00,000 in private colleges and INR 20,000 to INR 80,000 in Government colleges. Course Fees for BCA Colleges in Delhi range from INR 70,000 to INR 3,00,000. Top BCA government Colleges are Loyola College, University of Baroda, Ewing Christian College, St Bede's College, etc.