Yeah, back packers seem to be generally a decent bunch. Most thieves don't want to hike to steal!
I did meet some sketchy people on the Appalachian trail but I think that was because we were pretty close to a town.
You can practice setting up in a yard somewhere to get things started. You want to be able top get your tent up properly, filter water, and feed yourself. Pour over maps make sure you have access to water. Keep dry. Watch the forecasts closely.
i just got word from the boss that we're on for a ADK New Years back packing trip again this year, which is very pleasing to me.
Youtube is great but I'd really advise seeking out an experienced person to go with just to smooth out the kinks.