I always wear this piece of costume jewelry ring on my left hand (NOT ring finger, but the index finger)

He was playing with my ring as usual and decided to put it on my ring finger left hand.

We haven’t talked much about marriage and have been together for 2.5 years and he asked me to move in together next year, we’ve been house hunting for March)

I have this sneaky feeling he’s going to propose at the end of this month or on New Year’s because he’s been working A LOT, when he doesn’t have too. He keeps saying itself Christmas presents.

However, I’m not ready for marriage yet (want to focus on my career and financial goals), how do I bring this subject up without making it seem I’m suspicious or arrogant? Is him putting my ring on my ring finger a sign? Am I overthinking?