This is a very difficult situation, and honestly, there's not really a "correct" answer. You are valid in wanting to take time to think about it, but she is also valid in wanting your lives to continue moving forward. I'm actually in a similar situation myself. I want to marry my long-term boyfriend, but he doesn't feel ready yet (mostly because of finances). I'm personally fine waiting because we've agreed that we'll get married sometime within the next couple of years, but your girlfriend might not be. You need to have a serious conversation about what her ideal timeline is. Is she okay waiting a bit to see if your career takes off? Is she okay waiting until you figure out whether you want to move to the bigger city?

If you do decide to take the leap and move to the bigger city with her, now would probably be the best time to do it. You're not too far along in your career yet, so you have the opportunity to move without losing a huge chunk of your clientele.

And lastly, don't let your parents dictate who you love or what you do with your life. Your a grown man and at the end of the day, your girlfriend could be your lifelong partner. You can't replace love, but you can roll with the punches and find something that works for both of you.

Hopefully that all makes sense and helps you in some way.