Unfortunately, the OP was not “overqualified” for UIUC CS. The program has become their most competitive major to enter in recent years. They had an extremely high amount of very well qualified applicants this year, they received 3,200 applications in 2014 and over 4,000 in 2015. The average ACT score for CS was 34.6 for incoming freshman in 2014 and has likely grown. No one is “overqualified”. However I agree that OP has great chances at other schools.