Where to Stay in Cabo San Lucas

I am going to Cabo with my 18 year old daughter. My first question is can we stay in an "adult hotel" or does she have to be 21?
I would prefer a hotel that doesn't have millions of children everywhere. Is there a Cabo hotel that is in between?

Number two, we want to be very close to the town and on a swimmable beach. I have read there is only one beach people can swim at - Medano Beach - but it is often not swimmable. What is the truth? The Medano Beach Resort looks like a great location but I have read it is a party scene with techno music blaring all night long. What is near that hotel that would fit our needs/wishes?

We would also like a place that in NOT an all inclusive. And, we don't want to be bothered by sales people trying to sell us time shares.
I know this is a lot, but I need help.

Thank you,
Patti