Both my kids had them.
DD1's was nearly 100% and we got it snipped at 9 weeks, Breastfeeding was impossible and we were worried about speach issues.
DD2's wasnt bad at all, no issues feeding so we just left it.

I heard of someone who's three yr old, wouldnt/couldnt speak, worked out it was a tongue tie, had it snipped and she was as good as gold (she was being assessed for autism)

Its a personal choice, if she wants to get it done tell her to do it b4 12 weeks, because after that they dont like to do it because the skin gets quite thick and can bleed alot.
Also she might find that bub has to re-learn how to feed with a fully mobile tongue.
But fi she does get it done she wont have to worry about it causing speech and teeth problems.

The proceedure is done with no local or anything, the tongue is held up and the skin flap is snipped and gauze is put on in it immediately till the blood flow eases then they suggested feeding bub. its over very quickly