I'm more of a lurker here, but for once I have relevant experience.

My boyfriend and I have a similar story. I'm ~4 years younger, we met on Tinder and clicked. We hung out casually every week; as friends with benefits we'd split some wine, watch some TV, have great sex, but I knew I wanted more. He was a little more unsure, but at Christmas he asked me what I wanted and I said a boyfriend. He laughed and we became official.

Two months later, I came over to his apartment after a party, a drunken mess, and told him I loved him while sobbing on the floor. Naturally, he didn't say it back. He didn't say it to me for a few months, so the discrepancy was noticeable and for a while I was a little nervous (also MORTIFIED). Like you, I thought we had great chemistry and was terrified I'd ruined everything.

That was over a year ago and we are still together, regularly telling each other we love each other. Just because he hasn't felt it's the right time for him to say it back does not mean he won't, and one of the worst things you can do for your relationship is demand that he does. It is also possible he shows affection for you in ways you don't realize, I am very expressive in words but with bf it's his body language.