I'd be interested to see actual data on that. For example, a Canadian study done after a year of legalization found that more youths tried marijuana, but that they were trying it later than average and the overall usage of cannabis among youth remained the same. Interestingly, there was also an increase to the perception of harm from using cannabis among the youth surveyed.

https://doi.org/10.1016/j.jadohealth.2022.09.003