You already know each other as co-workers(which might be perfect from understanding background of each other), so that is something that might last, unlike with someone you have to go to date and know each other and generally have to be... I even can't be bothered to continue. I would not worry about age, because women age much faster than men and they have these worries about age as well and mostly about their own age. In 25 they might be at their best attraction point and couple of years later not many young and even older guys are chasing them. Though, I would not even use this as an argument in company of ladies, as this thinking would be considered is cheating in life code.
A friend of mine is 46 and have ~15 years younger wife and they are married for 10 years and have 3 kids.
I could list more of examples I've seen with age differences and how they work well if they are married - not really good examples on long lasting cohabitation(where I have seen them fall apart also after a very long time together), though - maybe because they had no children and common responsibilities and dedication to share things together. Yes, there are examples where families fall apart with children, but they had not 10+ years age gap, so with this limited data set of mine, I would say, that age gaps works better, than not having one. My grandgranddad married 27 year old, when he was 19, so that works other way around, too in my family.
However, just a question - since it seems, that you broke up with ex, because you didn't want kids is this different now? Maybe talk these topics out sooner and clarify when and why and the sooner the better. I had similar issue with my ex girlfriend, who didn't wanted kids, and at most only 1 and then probably in far future... probably not with me, so I did not took it very well and eventually we broke up. So, I guess your wording also was not too careful...
Not sure, maybe this is some influence on matriarchy(I had only females around me), so not sure if this is completely perspective of a male, but as a person I still want to understand from other person about their vision of how things will work out and what they plan to do to achieve them and what is what they expect from me etc. it is hard to explain, but anyway - even if you are 39, the person at 25 is not a child anymore and can take their share of responsibility, even when dating much older male.
I guess, they also can be regarded as co-workers:
Best of luck!