She only responds on weekends...

I am a 25-year-old guy and have been dating a girl two years junior for around six months. I like spending time with her, but I have noticed that she calls me only when she needs something. Whenever I message or call, she rarely responds until it’s the weekend and she wants us to make plans to go out together. I have asked her about this repeatedly, but she just laughs it off and says she’s busy on weekdays. I don’t want to end this relationship for something so trivial, but I wonder if it’s setting the right tone for how things change in the future. If we decide to get serious in a year or so and she continues to behave like this, I don’t know if I will be able to manage. Am I asking for too much? Should I wait and see if things change as we get to know each other better?
It has been six months, as you point out, and all relationships go through a learning phase where partners learn to understand each other better. It’s great that you have pointed out what you have a problem with, and while your girlfriend’s response may not be encouraging, it’s the start of a conversation that should lead to some changes as time goes on. If this doesn’t happen, you are either not getting your point through with the seriousness it deserves, or she isn’t taking it as seriously as she should, which shows a lack of respect for your feelings. Keep having those conversations, call it out whenever you feel as if you are being dismissed, and wait. If nothing evolves, you will have a better idea of whether this relationship has a future.

Should I be with someone just because I don’t know if I can find someone better?
It may seem like a sensible reason for now, but it’s your life and you are the one committing to spend it with someone. Put your interests first before making any decision.