Was she not interested or was she just not that great at initiating things?

So I'm trying to do a better job of learning from past mistakes and I've been thinking back on the experience with the most recent person that I dated. We dated for two months and things ended because I attempted to define the relationship and she said she didn't have any romantic feelings for me. Throughout the experience I noticed that I initiated a lot more than she did. This included reaching out and scheduling dates, texting conversations, physical contact, and sex. Sure there was a time or two where she initiated each of these things but overall I felt like I was doing a lot more of the legwork. Granted when I did initiate, for the most part, she responded positively up until the last couple of weeks. So my question would be does lack of initiation generally mean someone is uncertain about you or uninterested in you or is it just the norm that the guy does a lot more of this sort of work in the first few months of dating. I'm trying to decide whether I need to take this as a red flag or not in future dating scenarios so I don't waste my time.