Out of the 12 girls, there will be only one that is the lead-off batter.
we can assume that this is the first being selected at random, then the probability that you will be the lead-off batter, is equal to the quotient between 1 (the outcome where you are selected) and 12 (the total number of outcomes)
Then the probability is:
P = 1/12 = 0.083
The fact that there will be an arrange of only 9 girls does not affect the probability of you getting the position of the lead-off batter.
