I don't have any experience in co-sponsorship, but I think they do accept the beneficiary's assets, too. What kind of visa are you trying for, K1 or K3? You can read the instructions of the sponsorship forms (I-134 or I-864), it may have info there.
25 years is a big age difference for India, especially when the USC female is the older one. They also don't like it if either person has been married before and has children. However, many people have been granted the visas so you can do it too! Just have plenty of proof from a long courtship, and be fully confident in the interview. I am the female USC 16 years older than my Indian husband, and we got approved fine! Good luck to you!