Only if the girl lives in a vacuum, with no other influences. If she has a family and friends, goes to church and school, competes in sports or learns to play an instrument, the chances are she'll have get idea that life has ups and downs, and achievements usually require effort, before she reaches adulthood.
The real risk of producing children with unrealistic expectations arises when adults insulate children from the realities of life: ban games or contests because everyone can't win at everything; fight about grades, instead of letting children get the marks their work deserves; argue with coaches or umpires, instead of letting children learn that sometimes life is (or just seems) unfair, and so on.