Planning to move soon

I (early 20s F) have been living with my best friend/ roommate in our current apartment for just shy of a year now. We live in a MCOL city in the northeast and both have decent jobs. I’ve been job hunting and interviewing for roles in my dream city about 6 hours away.

We both know this living situation isn’t necessarily permanent, she has family in the area and I do not. I don’t know how to tell her if/when I get a new job that I will be moving, I don’t want to ruin our friendship or make her feel rushed to pack up and leave. I also am unsure how long it will take me to find a good enough job to move, so it could be anywhere from 1 month to 6 months, which is why I haven’t mentioned it yet since I dont want to stress her out or plan to move out before I do as she has support in the area and I have no where to go.

If I did suddenly land a job and move, I did plan to pay my half of the rent for another month or two to help her have time to move. Is this rude of me? How should I go about this?