Chubby fingers but he wants to get me a matching ring

Sarah • Real life sapiosexual. 1999💙End stereotypes. US size 20👸 ed warrior & former UN delegate. Honoring my big sister 1997-2019♥️

Sooo, here’s a side affect of being generally self conscious. I am so excited about the emotional portion of my relationship. He wants to have me pick a tungsten carbide ring so we each have one. I’m looking at colors, finishes etc but I’m stuck on one thing. The thickness of the band. I’m my head a bigger band 4mm+ will make my fingers look chunkier. I think I like 3mm because I don’t want issues bending my finger and I like a slightly daintier look. I want to get properly sized at a jeweler but I’ve always felt like my hands were ugly. I really dislike having my nails painted so this ring will be the main decoration in that area. So far I want a ring from Etsy. He says this is not really an engagement ring, basically a promise ring. I do wonder if I should stick with 2mm because I’d likely stack it with further rings like engagement and wedding band? Anyways I’m a bit lost here but at the core, excited 😭❤️ I would love some general ring advice with sizing, care, etc.!🙏 I’ll be in school till I’m newly 23 + looking for work and that’s when we can get married once I’m settled in a job 🥰