It sounds like there was something specific you did that led to the breakup. Maybe you neglected her or spent too much time gaming and not enough time with her, which could have made her feel unappreciated. It's also possible that there was some sort of miscommunication or misunderstanding that made her feel like you weren't on the same page or that you weren't supporting her artistic pursuits as much as she needed.
Another possibility could be that you might have said something that upset her, perhaps inadvertently related to your different interests or lifestyles. Given the teenage drama angle, there could have been an emotional moment where your gaming priorities clashed with her needs, leading her to decide to end things. How am I doing so far?