Adjusted for inflation, movie ticket prices are pretty static; there's some variation, but current prices aren't abnormally high.
1992 was, actually, a notably cheap year for a movies (ticket prices dropped, even before accounting for inflation, from 1990 through 1993), but even so, $3 ($5.23 in current dollars) was well below the average ticket price ($4.13; $7.21 in current dollars ) in 1992, $15 is nearly double the average ticket price (~$8.89) today.
And inflation-adjusted earning power (whether you look at median wage or median income measures), while some measures have been relatively static over the last several decades, and generally have underperformed aggregate output growth, were actually lower in 1992 than today.
See, for ticket prices, http://www.boxofficemojo.com/about/adjuster.htm
Rural/suburban theaters (built and owned on cheap land) that OP may have gone to as a child will certainly be cheaper than urban theaters (high rents) frequented as an adult.
$15 is cheap for a ticket in an urban/wealthy area.
When I worked at a big mall cineplex in the late 90s, I'm pretty sure it was $7.50. They had a weekday combo where two tickets and a small soda/popcorn was $20.
I don't have access to theater demographics, but anecdotally, the makeup of a Friday night crowd seems to skew older and have fewer groups of kids. That might be more about malls dying than movies though.