NIEM- The Institute of Event Management, Mumbai

Yes, you can definitely do BBA from any college even if you are from science college. There are as such no norms by any college if you want to do BBA after science stream in 10+2.
BBA is not hard for anyone for any stream if they come in it. Many students do another course in graduation like B.Tech, BCA etc. and then they do MBA. If you want to come in the Business Administrative field then you can go without any tension. BBA is related to Business Administrative i.e. a managerial field. After doing MBA you will find the Managerial job in any company. If you have passed 10+2 then you can go for BBA and this stream is easy for you.
Believe me as a fact you might feel the course a little difficult for first few months but later science stream students score much better grades than commerce students.