Your drive train will wear faster using a 12t front.
This is a true fact. Not a factor in reality, imo.
I bought a new chain slipper when I bought my first 12T cuz I was sure I'd be needing it.
Haven't put in on yet.
After riding most every weekend..commonly 50-75 miles a ride,
for over two years !! I had adjusted my o-ring chain once.
Sure, by then it was getting to be time for a change of drive train components.
A 12T front will fit with the 108 link oem chain. If you don't like it, or want to change back to the 13T, you can do it in a minute or two.
You won't be doing that with a 50T rear.
If you haven't changed your chain yet, do it. Running the oem chain is a waste of time. You'll destroy your sprockets and the chain in very short order. Save your sprockets now! Put on a decent chain.