I'd definitely try. Some little kids won't even keep their shoes on when they're cranky, but mostly I've seen little kids being better about it than adults and older kids, at least on what I assume are short trips like to the grocery store. Like I've seen families with multiple kids under ten who are all prancing around happily with masks on, but the adults have theirs pulled under their nose or don't have it on at all. I know someone who said his girlfriend told their 3-year-old they were playing peekaboo but they couldn't do the "boo!" part until they got home (which is true, that's what they're doing), and it completely worked and continues to work.