18 was a long ass time ago for me. It would have been the late 90’s. The world was so much different that I don’t think anything I could say in 3 words would make any sense to my 18 year old self. I didn’t have any money at 18 so something like “buy apple stock” wouldn’t have worked.
Even taking the big assumption that I believed what I was telling my 18 year old self I can’t actually come up with anything that makes sense in context. 3 words just isn’t enough to convey anything useful given the time difference and everything else!
I’m sure this will be lost in the comments but you CAN get 25GBit here in 'murica. My ISP offers it… But this ISP is also considered one of the best in the world so… https://epb.com/fi-speed-internet/#choose-your-plan