18 is a legal age and is a consenting adult in most states in the USA. So it really should not be any of your business who's fucking who or dating at that age for that matter. Obviously, if it's someone under that then that 100% should be reported to the authorities. I lost my virginity at age of 17 but I was living in New York at the time and my girlfriend was 18 years old. New York's age of consent is actually 17 years old if you were not aware but in Florida (where I am now) is 18. I am not sure why that is, but I do find that rather odd.
My sister was 25 and she married her boyfriend at the time who was 35 which is a 10 year difference. When I was in my early 20s (about to turn 36

) I had sex with women ranged from my age group and close to 50s, so get the fuck out of here with that bullshit. There are also plenty of women who prefer older men whether it be because of financial security or even looks. There are plenty of older guys who still look good, age is a lot worse for women anyway's when it comes to beauty standards. Then again, I've seen a good share of 50 year women with so much plastic surgery and bbls that they make a 20 year old look ancient. I live near Miami, this is the center of fake people, shallowness and hot looks and show-offs. So older women here looking like 20+ year old models is very common here and seeing an older man surrounded by multiple much younger women on his Yatch is VERY common.
Also, here is some more education for you and fun facts:
"In the United States, 7 states set the legal age of consent for sexual activity at 17 years old:
Colorado, Illinois, Louisiana, Missouri, New York, Texas, and Wyoming. In these jurisdictions, individuals aged 17 or older can legally consent to sexual activity
- 17-Year-Old Consent States: Colorado, Illinois, Louisiana, Missouri, New York, Texas, Wyoming"