i like my guy friend and i don’t know what to do

So I’ve been friends with this guy from college for about 2/3 months. We met through a mutual friend in january and we went for coffee, and he invited me to go climbing with him. we’ve been going ever since every week, sometimes with a few of my friends from college who enjoy going too. now from my perspective we’ve been flirting a little, but i’ve been known to be delusional in the past so I am unreliable with these things. I really like him, i thought he was cute since I’ve met him but our friendship has only been platonic and he hasn’t really done anything to suggest anything further. he’s quite reserved and quietly spoken so it’s really hard to tell what he’s really thinking. i don’t know whether to up the flirting and see if he reciprocates, straight up tell him, or just bury my feelings and forget about it. I also am just straight up scared of being rejected lol! any advice would be greatly appreciated 🥲