Start flying with glider self launch certificate?

Is it harder to get a first pilot certificate for glider - self launch vs. normal powered aircraft near St. Paul, MN? It seems like a self launch glider certificate would be a great way to start because of better stick and rudder skills, lower age requirements (for my son), cheaper operating costs, glider hours apply toward power aircraft requirements, etc but I'm concerned that it might be a bad path because it appears to be rare and hard to find instruction near St. Paul, MN.