She’s in a relationship with another guy and I love her so much.

i am a 20 year old guy dating a 23 year old lady and shes in a relationship with another guy and i love her so much,she loves me too,she usually reminds me that shes older than me and we’re trying our best to hide it and she always blames herself for the fact that she older than me,and this makes it harder to take our relationship to the next level,what should i do?