Regular script appeared later than official script, and it is closer to modern font. If learners are young (3-6 years old) and regular script is easy to identify, it is better to learn regular script first. However, it is old and strong, which is of great help to Weibei's future study. If he has a solid basic skill in official script, it is not easy to write the same words, which is urbanization.
My experience is that it is good to learn official script first.