Hi TheKdd,
Thanks for the update and for taking the time to share your experience … I appreciate it
While there is a wide range of heights available for bedframes, foundations, and mattresses which together will add up to the height of your sleeping surface … a typical metal bedframe is about 7" - 7.5" high and a “standard” foundation would be in the range of 8" to 9" so the combination together would normally be somewhere in the range of 15" to 16.5". A fairly “standard” height of a sleeping surface would be somewhere in the range of about 26" give or take an inch or two so yours (14" + 13" = 27") would be in a fairly “normal” range although it may be higher than what you were used to with your previous sleeping surface.
This would be normal for any foam material (to different degrees depending on the type and density of the material) which will soften more under the more concentrated weight of sitting … particularly in the first few months.
I would definitely suggest rotating your mattress on a regular basis for any mattress to even out the softening (see post #2 here).
An adjustable bed or a foam wedge behind your back (something like one of these or this) will also support some of your weight and reduce the weight concentration when you are sitting up and help slow down the process.
Phoenix