Amazing man... but I feel closed off?

I just recently starting seeing an amazing man. It will be four months of seeing each other.

He is incredible in every way. He is my best friend, we joke, we laugh, I am incredibly attracted to him, and I truly love and adore him. He is the most uplifting and rejuvenating energy to be around. Yet, I feel that I have this wall down whereas he is so open to express his love to me.

I can see a future of us together and he is one of the most incredible humans I have ever met. And I want to take this wall blocking me down. When I was in high school I was in an abusive/controlling relationship, but what I feel the most relevant factor is my mom telling me not to date, love or let my guard down. She says “guys suck” and “keep your guard up” and “don’t date until you’re 30, you’ll get distracted on your career.”

I can’t get the stupid voices out of my head. I want to let all my shields down and love him as freely as he loves me. I know I do love him but sometimes I feel a knot in my chest and throat that I’m doing something wrong. He is the most kind and caring and loving person ever. Please help!