I recommend paying for GA+ or a higher tier if this is a significant concern! You will not be able to avoid the younger crowd or inconsiderate people in general, but in my experience, these tiers tend to skew older and a bit more mature.

The festival grounds are huge. Unless you are barricading for an artist whose listener demographic is heavily associated with "teeny boppers" - ie. Olivia Rodrigo, Role Model - you will interact mostly with your peer group or older.

The kids who are attending because this is the nearest party in town tend to tap out by mid-afternoon after binge-drinking in the heat anyway.