Sex on the first date?
I'm 50 (way crusty!) and male, and I've made nearly every mistake it's possible to make with ladies. And on other occasions, done lots of things right, too.
I've played my cards wrong and lost out with women, by appearing too interested or too uninterested, being too eager or by not picking up on the cue that said 'I want sex now if you just give me the right excuse'. And I've been at various times a slut, a player-wannabe, a shy boy, an awkward geek, a one-nighter, and a confident guy who knows what he wants.
On many occasions I've been fortunate enough that a series of outings or dates led eventually to a relationship. I've had just two occasions when we both just had sex by obvious mutual consent at the very first opportunity. You know what I called each of those two ladies?
"Fiancee". Later, wife. No regrets. (first marriage lasted 15 years, still friends). Those occasions where it just feels right, sometimes it's just right.
So if I went by my own experience, I'd say Dale and Marigold just did the right thing and are destined for a long and happy thing.