My doctor told me that hip replacements can be put in with or without cement. Evidently I'm young enough to have an uncemented one. How old do you have to be for the cemented hip?
Age may be a factor in whether the surgeon uses cement or not, but the real issue is bone density. Older adults are more likely to have decreased bone mineral density. A cemented implant may be needed for patients with osteoporosis or brittle bones. The cement helps hold the implant in place when the bone grows around it is very slow.

Younger, active adults with good bone density do well with uncemented implants. In fact studies show that uncemented stems in the femoral component are less likely to loosen in the second decade. As a younger adult, the survival advantage of the uncemented total hip replacement will be to your advantage.