There are varying degrees of being tongue tied.
When I was a child, I had a friend who was tongue tied. It did affect her speech, etc.
She showed it to me and I said, "Why doesn't your mom just take the scissors and snip that thing?"
It was literally just a tiny thread of connection from the tip of her tongue to underneath it. It was thinner than a strand of yarn, but quite short. As a kid, I just remember thinking if it was me, I'd have snipped it myself.
Your baby is only 1 week old. If she is eating okay, I wouldn't think there would be a real urgency at this time to do anything about it. If it begins to create a problem, follow up a little more on it.
For now, if the doctor isn't concerned, you don't need to be either. This is something that can be corrected down the road if need be.
Best wishes to your little one!