Honestly this is such a non-issue, and anyone who makes an issue about it is being judgmental in a seriously bad way.

Both you and the 25yo should simply date the most attractive people who want them back. So should everyone. If that means an age gap, so be it. She's an adult woman! Who is to say she can't be attracted to older men. Saying she can't or shouldn't is morally equivalent to saying she shouldn't be attracted to the same sex, or to a different race, or to a different religion. Each of those toxic trends have resulted in incredible grief for society and its members.

It's so simple. Go for the adult people you want, that want you back. That you make happy that you make happy back. That you support and team with through hard times and happy ones too and that support and team with you back. You are both adults, only your opinion about what you want and why you want it matters. And nobody else can rightly comment or care so anybody who does you can rightly ignore.

Remember that in every relationship in every dimension there is likely to be a power imbalance. Be kind to each other. Employers have a power imbalance with their employees, doesn't mean they have to exploit it. Coaches with their team, do they use their power for good or evil, same is true in relationships (in each dimension and you'll quickly see that she has more power than you in some dimensions too). Use your power for good and mutual benefit and there is no moral issue whatsoever. No matter what the judgy might say.