I am having Air 2020 and Pro 2019 side by side...
if you ask me, the size and weight diff is ignorable...

Air i5 1.1 vs Pro i5 1.4...gain a little...
price match but u have 512GB vs 256GB...
so if u don mind of carry extra storage around...yea pro probably a preferred choice...
a 2nd thought is the RAM...but unless she is doing something heavyweight...8 still can survive...
but 16 is highly recommended
unless u can get a CTO version, maybe u could consider Air i5 1.1 + 16GB + 256GB

yup definitely its a no brainer now given all updated, and when u put Air i5 base vs Pro i5 base...the diff is too little to call for the lesser...
to share a bit...I used CineBench on both
Air with i5Q 1.1 + 16GB vs Pro with i5Q 1.4 + 8GB
CineBench score for Pro still double of Air...so no way u go with Air unless for the cheapest i3, though 512GB at hands without need to carry a thing is plus...

Enjoy the Pro~