Your mash temps may be okay. From what I have read, the temperature in the thin part of the mash is what is most important as that is where the enzymes are at work. That is why you can do decoction. I assume the inside of the bag is where the thick part of the mash was. Even if you were in the mid 150s, you will still have conversion. Your beer may have more body and malt character. Chilling to 73 was actually good. Jamil suggests pitching slightly under fermentation temps and letting the temp rise to fermentation temps. You will have fewer off flavors.
Congrats on first batch.
Reason: Mistake. Said outside meant inside