Taylor came out and said the exact same thing as this like only a month ago.
Before you know who you are in a relationship, you have to know who you are by yourself. Most people in their late teens/early 20s are still figuring that out. You're constantly changing and you're a completely different person to the person you were only 6 months ago.
For most people, your first few "relationships" aren't even relationships at all. I'm talking about the ones that last less than 5 months. They're just stepping stones in figuring out who you are.