Hello !
Yes definitely you can pursue bba despite of being a science student. It is no problem. You can easily cope up with the commerce syllabus. It although takes time and dedication to fully understand the commerce subjects like accountancy tax audit etc in depth. You will have to spend more time learning the syllabus and you can definitely outweigh the commerce students.
Bba is a great course to pursue with an interesting curriculum and good opportunities .
Hope this helps
Thank you!