Is it a good time to say it back?

Two weeks ago my boyfriend asked me if I loved him and I said i was not 100% sure but that I know I really like him and that it would be hard not to fall in love with such an amazing guy. Tomorrow, his mother invited me to join them for new years eve. I keep replying I love you to him but only inside my head. I stare him straight in the eyes when he says it and I hug him but I can never bring myself to actually say it. Mainly its because not too long ago I was telling him I needed time. I was thinking of saying it some point tomorrow.