89.4 is a good percentage in 12th boards and you can get computer science under pmsss but the main problem is that this year due to internal assessment and no exam, students have got above 90% in their boards. The competition is really tough so getting CSE in top colleges of Pune may be possible and may not be possible. COEP, AIT, etc are some top colleges in Pune in which students have got CSE having scores above 90% but this year we cannot say anything.
Dontworry there are many good colleges in other cities also where you can get the cse branch. Ensure proper choice filling and for your information, the application has begun for 2021. You can check more details from here