...and the answer is........
"It's as long as a piece of string" !!!!
Varies tremendously upon age, skill, co-ordination level of student as well as factors such as weather, instructor compatibility, length of time between lessons, etc etc.
But a few basic questions to you.....
1. Is the "crosswind" situation being brought up as an excuse by the instructor, or is the instructor still working on your general flying handling abilities?
If answer is "crosswind" then could there be other fields you could use for practice?
2. Where are you up to in terms of handling? What exercises have you done, and are you repeating certain exercises (and why?)
3. Have you mentioned your concerns to the instructor? What did he/she say?
4. How much ground briefing have you had from instructor on circuits and landings?
Forming a picture of where you are and why on your course is important before anyone responds (and possibly jumps to conclusions).