I'd wait a few weeks to a month and then if the baby tooth
still hasn't fallen out, try going to the dentist. For these types of things you really just have to eyeball it.
This hapened to one of my DD13's bottom front teeth when she was six, luckily it wasn't that bad, even though the tooth had completely grown in. She's the only one who this has happened to (so far) unless my DS's impacted wisdom teeth count. It just fell out when it was ready which didn't take long. The new tooth was directly behind the baby tooth and shifted in perfectly once it fell out. She was happy that she wouldn't have a big whole in her mouth, though at the same time complained "But no one can tell I lost a tooth!"
However, one of the last teeth she lost (this was just a year ago) was a front tooth (the third one in) which had the adult tooth coming in, but it didn't look so good. It was coming in on a diagonal because the baby tooth was blocking it, actually pushing it forward a bit. The tooth would not fall out, wasn't even loose, I couldn't get an appointment at the dentist (took me
three months for them to look at my chipped molar) so I just had to keep telling her to tug on it. Finally after about two months it came out, but the adult tooth was messed up. The one on the other side came in beautifully and looked perfect, but the shape was off (which may have caused the problem) and the gum was up pretty high, exposing a lot more of the tooth. It did shift back to where it was supposed to be, but it's still a little more forward than it should be. She hasn't neeeded braces or anything, you really don't notice much of an irregularity unless you examine her mouth.
Just keep a good eye on it, there's no need to fret unless it's looking really irregular.
