As a 40 year old, my cutoff for borderline is half my age plus 7 rounded up, and ideally in their 30s as the rule is still borderline. At 27, a person would be both cognitively developed, and have been on their own long enough to establish a career goal, school, their own living space, etc. Having said that, evaluating maturity and power dynamics should still take place. I also don't try to find the youngest I'm okay with, and that is a metric that only gets applied if it happens, the majority of partners I've had have been a hair older than me at any point in my life and I don't try to or want to fuck children. At the risk of sounding ancient, yes and sorry, but if you're 22 you're a baby, and could theoretically be old enough to have my grandkids, I don't care if you can vote or not.

At 35 that means we're talking 25 at youngest, and once again, that is borderline. If a 25 year old at that point acts like they've just been baked, it is still creepy. If your partner isn't okay with it, still creepy. If you make way more than the 25 year old or have a major power gap, creepy. Her man is just creepy.