The answer is yes, and there are several explanations. Some women have menstrual cycles lasting less than 28 days. If a woman's cycle lasts 22 days, and she ovulates at mid-cycle, a pregnancy is possible on day 11. Wed MD explains that menstrual-cycle length can vary from month to month.
In another case, ovulation can occur earlier during a shorter cycle. A woman can ovulate on day 11 or earlier as opposed to day 14, or which ever day marks the midpoint of the woman's typical cycle.
A woman can become pregnant days after having sex, because sperm can live for up to 5 days following sexual intercourse. If a woman had sex as early as day 6 of her cycle, and she ovulates on day 11, she can become pregnant as a result.