Well... Since I'm old, I think I stopped caring about size! LOL But truly, you should choose whatever size you want - there's no such thing as too big (IMO), only what you're comfortable with :)
If you'd like to go bigger than 10x7 (& don't mind buying outside the U.S.), please don't let the price limitations stop you. There are very affordable overseas options (lots of info listed in the wiki re: the vendors).
You could even purchase a loose oval, and have it set locally :)
You've probably already seen this, but just in case, here's a link to diamdb: https://www.diamdb.com/compare/3ct-oval-10x7x4.5-vs-4ct-oval-11x8x4.5/ I popped in 10x7 and 11x8 oval comparison on a size 6.5 finger - but you can adjust everything down to screen size :)
I've noticed that compared to rounds or rectangular/elongated cuts, that ovals do face up a bit smaller. Due to the rounded corners. I was so surprised at how much smaller a 10x8 looked once on my hand :)
Another great way to decide, is to purchase a couple inexpensive CZ rings to test drive :) I don't think I've seen 10x7 while digging around on Amazon, but you could at least get something close... Here's a link to a platinum plated silver one for under $30 (might be a little big - 10x8.5): https://www.amazon.com/dp/B076HJTGRR/ref=cm_sw_r_sms_awdb_imm_S5FJV2XAVETEK54XGEKH?psc=1
This one is a little smaller & around $13: https://www.amazon.com/dp/B0857HHBQF/ref=cm_sw_r_sms_awdb_imm_QSY93WSFAWT971RPE9DQ
There's tons more of course - and I've purchased them off of eBay also... :)