Is it possible to change the calendar meeting time reminder so that it isn't always fifteen minutes?
All appointments made in your calendar have the default reminder warning time of 15 minutes.  This means that 15 minutes before every item on your calendar comes due, a reminder notice will pop up on your screen.

When setting up the meeting you have the option to choose from a predetermined list of reminder times but what if you want to have a distant reminder, say one that reminds you to begin prep for the meeting weeks in advance.

You can easily set any other reminder period you want, not just what is listed in the dropdown. If you want to set the reminder to 11 minutes, type 11m in the reminder field. If you want 2 days, type in 2d in the field. 4 weeks, type in4w.
When changing the time period make sure you type in the right letter value:  m for minutes, d for days, and w for weeks.