Funny, I just want through this again last week.
I originally started with the 2017 MBP 13 i5/512/8 model. Was able to exchange it to the 2018 MBP 13 i5/512/8 model. Felt really small, and was able to exchange it for the 2018 MBP 15 2.6/512/16 model. Though it was a great machine, had no problems, I just didn't like the overall size. I also found that I didn't need the extra cores nor the Radeon 560X graphics. I don't do a lot of video editing, and well, gaming? I have a Xbox One X and a custom built PC for that. So fast forward to a couple weeks ago, my wife wanted a new laptop. I showed her the new MBA, she loved it and I bought it for her. While setting it up, I totally fell in love with the size and weight of the 13. I found I could live with the smaller screen.
I unfortunately had to return her MBA as it had a major problem with turning on after opening the lid (as it wouldn't turn on at all and per Apple's request, exchanged it). However, after 2 attempts at returning it, I could not get a screen that was as bright and vibrant as on the 1 I originally returned. Instead, I bought her a 2018 MBP 13 i5/256/8 when Best Buy had the 1 day sale 2 weeks ago for $1499.
Last week, I sold my 2018 MBP 15 and purchased the 2018 MBP 13 i5/512/16 from B&H while it was on sale. Overall really happy with the 13" screen size and weight. Feels well balanced in my lap as I type this, the fans remaining silent, and overall is really well balanced. I much prefer the typing deck on the 13 vs the 15. I thought the 15 was kinda to big for my wrists to rest on and sometimes the sharp edges would dig in.
The 2018 MBA is a nice machine. I prefer the angled deck compared to the MBP as its much more comfortable to type on. I think you will be fine with the 13".