If I score 300+ will I get top college on the Ipu for IT

You get admission into colleges based on your rank only, and rank depends upon many factors like number of applicants fill the form, number of applicants finally appeared in the exam, number of questions asked in the exam, difficulty level of the exam, performance of the candidate, previous year's cut offs trends availability of seats in the institution. Though you scored very well in the exam so I am sure you'll easily get seat in CSE/IT in top colleges. You can also predict your rank by the help of our rank predictor.

https://engineering.careers360.com/ipucet-college-predictor

And you can also check what colleges you might get with your rank by going through this link.

https://engineering.careers360.com/articles/ipu-cet-cutoff

Good Luck!!