Hello vanshita
First of all,I would like to tell you that there is no condition for the choice of extra subject to get admission into B.tech in any branch.Admission to Btech course in any college solely depends on your entrance exam rank.It's just that if you had IP as extra subject,you might had a prior knowledge of java but then again,that doesn't matter.So yes,even with P.Ed as your extra subject,you xan get admission to Btech in cse.Hope this was helpful.
Good Luck!