Hey,

Yes that possible. You can go for psychology honour without leaving science in your class 11th.

There are colleges or universities like Banaras Hindu University, Annamalai University andtand many more that offers BSC  in  Psychology courses to students and hence that makes their science in class 11th justified.

One main condition is that you need to have biology in combination with your maths subject in your class 11th in some places.

Check the university offering these courses from the link below and also check their eligibility,

https://university.careers360.com/colleges/list-of-psychology-universities-in-india

Hope that helps.

Thank you