Pausing or changing the time in any way causes aging problems. When you say it's not aging, do you mean the number on the stats screen is static or that it's been two days and it hasn't changed into a toddler/teen/adult? If it's just the stats screen, don't worry about it and remain patient. that number means nothing.
If it's not changing form, however, be sure to cut down on pausing, and if it comes to it, reset.