If you were merely charged with the summary offense of leaving an unattended child in the car, then yes, it is treated as a less serious offense---as opposed to a charge of child endangerment, which is possible in that situation.
The law is quoted below:§ 3701.1. Leaving an unattended child in a motor vehicle. (a) General rule.
--A person driving or in charge of a motor vehicle may not permit a child under six years of age to remain unattended in the vehicle when the motor vehicle is out of the person's sight and under circumstances which endanger the health, safety or welfare of the child. (a.1) Applicability.
--This section shall apply to the highways and trafficways of this Commonwealth and, for the purposes of this section only, the term "trafficways" shall include, but not be limited to, parking lots. (b) Penalty.
--A person who violates this section commits a summary offense. It is a separate offense for each child left unattended.
However, be aware that under PA law, you can be sentenced to up to 90 days in jail for each such summary offense. This is not just a traffic ticket. Because children are involved, and this can be a hot-button issue for some judges, I would not suggest that you go into court unrepresented. For your first offense it is unlikely that you will get any jail time. However, the offense has the ability to place a black mark on your criminal record
I wish you the best.