Based on your scores:

88% in 10th grade,

87 percent 12th grade PCB,

88 in the OUAT response sheet,your calculation is 0.25*88+0.25*87+0.25*88=65.75

As a general category student, you have a competitive academic profile for admission to OUAT. one need to have weightage of 70+ to be in safe side for general category candidates. The cut-off may go down to 65 but below 65 there is very less chance.you are on border line so hope for the best.