Are older men flirting with me or just being nice?

I’m a 26 year old female working at a grocery store. As you can imagine, A LOT of older daddies come into my store. I’ve been into older men since I was 16, something about them just turns me on, and I’m not really a fan of meeting people online or through apps. So when a silver fox comes through my line, gives me a big smile, makes eye contact, asks how I am and how my day is going, and tells me not to work too hard (😩🥵), I naturally assume they’re flirting or at least think I’m cute. I usually don’t flirt back too boldly or at all since I want to remain professional on the job, but MAN DO I WANT TO. Sometimes I feel like older men tend to hold back because they just assume younger women don’t want them, BUT I WANT ONE. Is there any way I can make it clear that I enjoy an older man’s advances? How can I tell (if at all) if an older man is flirting with me or just being nice? I don’t want to flirt back and all of a sudden his wife and kids show up lol.