Why would I be sent to PA for 7 weeks when I am reclassifying to 68W and have a class date this summer?

Yes, it is a 68W MOS-T class taught by the PA ARNG.
There are 22 active duty TDY enroute reclass in your class.
Active Component uses ARNG MOS-T and PME classes every month.
You're booked in the correct class.

As others have pointed out, the PA ARNG MBTS runs a MOS-T. It is much more cost effective then a seat in the entire initial MOSQ course and to be honest, the better option for you as well being "prior service". I attended the 16 week course when I reclassified and was a junior NCO. It was my third formal MOS course and there was so much unnecessary extra activities that we, as not only experienced in non MOS specific details like drill and ceremony and such that it was truly a pain in the 4th POC. From knowing the MBTS staff and how they function, you will also get much better training and exposure. Not to knock the DCMT staff at Ft Sam but they have a ton of students and some of the Cadre may or not have as much experience as the PA MBTS staff. Most of them have many combat deployments under thier belt and some of the older staff there actually help write the 68W POI. Past Cadre there actually won the Best Medic competition a few years ago as well. Top notch course to attend.

AIT seats are very hard to come by on Active Duty, so we get a few of them from the National Guard schools as well. You are going to go to Fort Indiantown Gap. It's not the wrong class. It is an accelerated program that the NG has for people who are already MOS qualified. As a former 68W, after you get your EMT cert knocked out, you could learn everything you need to know about being a medic in 3-4 weeks.