I'd echo what Kyokei is saying. Admittedly, some H boutiques have a more welcoming vibe than others. But I can offer an encouraging anecdote: I offered to go along as hover-in-the-background moral support for a college-age friend who was working up the nerve to make her first foray into an H boutique. (It wasn't obvious we were together.) My friend was neatly dressed and polite, went at a time that wasn't super busy -- and within 20 minutes had the SAs talking about how charming she was. She was quite honest about saying that this was her first visit, and that she was a little nervous to come in, but that it was her dream someday to own an H bag. She added that she knew H also produced beautiful scarves and bracelets. She was wide-eyed and appreciative, and the SAs seemed to enjoy her time there almost as much as she did. She didn't buy anything, but she left with a fistful of perfume samples; one of the SAs even made her a wristlet out of bolduc ribbon.
Anyway, just saying I've seen an example of youth and H-innocence actually serving as assets in breaking the ice at a boutique. Here' s wishing you similar luck, and a wonderful experience!