(23/M) My girlfriend (24/f) wants romance for Christmas

She said that she wants it to be like we're falling in love all over again. I have no idea what to do. We went to Denny's (a diner) on our first date, so I was thinking about taking her there and maybe writing a song on guitar for her. But she also really likes the moon, so I was thinking about taking her to a park or an observatory that has telescopes for some moon gazing or something. She also really likes coffee as well. I don't even know if that's relevant. I just don't want her to be disappointed, as I feel like I'm terrible in the romance department. Any help would be greatly appreciated :)