How do I approach the topic of Boundries?

My girlfreind and I have been dating for almost 4 months now and I dont know what her boundry are and I dont have a basis to go off of since shes asexual. How do I approach the subject of boundries? I need to ask her what shes comfertable with as I want to get closer and be part of her life.

Tldr: How do I approach the subject of boundries?