No average 15-year old can “work hard” and simply “earn” the enormous gobs of money this kind of collection costs.  Someone older who can be assumed to have worked their whole life and slowly accumulated a large collection, such a person have demonstrated dedication and sacrifice, which signifies genuine interest and love for the subject.  But someone 15 years old?  They <i>must</i> have simply bought it all, over a comparitively short period of time, for ungodly amounts of money.  And when neither time, effort or sacrifice is involved, it’s very hard to trust the person to be genuinly interested.<p>Sure, they <i>could</i> still very well be genuinely interested and dedicated to the subject.  But, while we normally can make the reasonable assumption that a person who owns a large collection necessarily is genuinely interested in the subject (per the above reasoning), in <i>this</i> case this reasoning is not valid.  They still might be genuinely interested, but we have no way of knowing that.