Parvo is awful and you are right to fear it.
That being said - I think that sometimes we can go too far in protecting our puppies. Don't forget that Mina is right in the middle of a critical socialization period! Mental health is just as important as physical health.
I think that confining Mina to your house until she's done with shots might be a wee bit too drastic.
You had the right idea all along - take her places that you are confident she will be safe from exposure. Just make sure you call ahead and ask questions so that you don't run into a situation like your friend's yard!
One of my favorite puppy socalization excursions is go to Home Depot (which is often dog friendly) with puppy and a big, clean towel. Put the towel down in a cart (to catch any accidents and keep the pup on a clean surface) and socialize with the customers! Basically, you don't want her walking where other dogs are likely to be. There are tons of ways to avoid that problem and still get Mina out and about.
It's also okay to arrange visits with
safe, healthy, gentle older dogs in a controlled environment.
Plus, puppy class should start for Mina soon, right?