Actually... It is a scam, I would recommend you not to waste your time with them. The quickest way to get rid of them and notice they are scammers is by either having a Google form or Ko-Fi Commission page and telling them
"Hello there, feel free to make your request in the following link" and the link to my Ko-Fi Commission page
The usually never respond, and those that do it totally ignore the link or greeting and go straight to their scripted wannabe attempt of a scam.
As well, the fact that they talk about inches when you're strictly a digital artist is also a big call out, most of the time genuine clients as in pixels or simply go "I want it be enough for a pfp but also to use in post"
And I'll tell you the following: They DO know english, they just pretend to play dumb or have very ambiguous phrasing to pretend to look like a an actual person typing through. Usually they show how well they write when it's about insulting you once they figured out you've been playing with them or just straight up telling them their scam doesn't work and to get a real job. Lmao
I would recommend you @sushy00 to read my previous reply slowly so you can properly understand how the scam works and how to see the red flags before hand more easily. Because to me this was obvious from the very first message.