Hello dear .

hope you’re doing well

Yes you can do b.com (//b.com) hons from DU school of open learning even if you studied PCB in 12th.

The eligibility criteria to get admission in b.com (//b.com) hons in DU sol is you must have scored a minimum percentage of 45% in your 10+2. There is no age bar to get admission.
admission is given completely on merit basis. For more details please look into the below mentioned link

https://www.google.co.in/amp/s/university.careers360.com/articles/du-sol-eligibility-criteria/amp

Good luck!!