This is not an islamic conduct and i've yet to see or hear of such cases. As you're well aware the prophet ﷺ waited until her physical maturity and muslim should follow suit.
Is there evidence for this? Mind you i'm not a scholar i'm just contributing with what i know.
In surat al-nisa verse 6 allah swt say.
وَابْتَلُوا الْيَتَامَىٰ حَتَّىٰ إِذَا بَلَغُوا النِّكَاحَ فَإِنْ آنَسْتُم مِّنْهُمْ رُشْدًا فَادْفَعُوا إِلَيْهِمْ أَمْوَالَهُمْ ۖ وَلَا تَأْكُلُوهَا إِسْرَافًا وَبِدَارًا أَن يَكْبَرُوا ۚ وَمَن كَانَ غَنِيًّا فَلْيَسْتَعْفِفْ ۖ وَمَن كَانَ فَقِيرًا فَلْيَأْكُلْ بِالْمَعْرُوفِ ۚ فَإِذَا دَفَعْتُمْ إِلَيْهِمْ أَمْوَالَهُمْ فَأَشْهِدُوا عَلَيْهِمْ ۚ وَكَفَىٰ بِاللَّهِ حَسِيبًا
Test ˹the competence of˺ the orphans until they reach a marriageable age. Then if you feel they are capable of sound judgment, return their wealth to them. And do not consume it wastefully and hastily before they grow up ˹to demand it˺. If the guardian is well-off, they should not take compensation; but if the guardian is poor, let them take a reasonable provision. When you give orphans back their property, call in witnesses. And sufficient is Allah as a ˹vigilant˺ Reckoner.
Now we focus on حتى إذا بلغوا النكاح. What does it mean? It means until they reach a marriageable age. Here you can see that allah swt establishes that there is an age for marriage in islam but didn't we say that marriage can happen at any age? Yes this verse speaks of consummation age not marriage age. The age of nikah, marriage or in this case the consummation of marriage is translated by ulima in the case of boys when they get a wet dream and in the case of girls when they get their period after which they can consummate the marriage because now they are able to procreate.