By NICOLE BODE
Little did she know her hours of mental preparation would pay off - possibly saving the Brooklyn girl's life.
Last night, the 4-foot-5, 80-pound sixth-grader was hailed as a hero for fighting off an attacker twice her size - then having the wits about her to help capture the suspect.
"I always make my plan before there's a robbery or a kidnap[ping]," Xochil said from her Midwood home. "I think of a plan, like, if anybody kidnaps me, kick them back or scratch them - I'm growing my nails out. I went with Plan B."
Plan B meant yanking backward with all her might as Bernard Mutterperl, 19, allegedly grabbed her in her apartment stairwell Sunday, dragged her into the lobby and tried to take her to another set of stairs leading to the roof.
But Mutterperl, who stands 6-foot-2, had picked the wrong target.
"I always tell her, whatever happens, whatever these men do, don't go with them for anything," said mom Martha Hernandez. "Thank God she knows how to defend herself."
Xochil was heading home from the corner store with a new bottle of nail polish for her mom on Mother's Day.
The street-smart pixie spotted Mutterperl tailing her about a block from home and instinctively began to run for the door.
But after making it up two and a half flights of stairs in her building, Mutterperl grabbed her just short of her apartment, she said.
"He grabbed my mouth and told me to not scream. I thought he was going to take me up to the roof and rape me or something like that," Xochil said.
"When [we] went downstairs, he loosened my wrist a little bit. And I took advantage of that and I broke out of where he was holding me and I ran outside."
Mutterperl was arraigned last night in Brooklyn Criminal Court on charges of unlawful imprisonment, endangering the welfare of a child and burglary. Bail was set at $25,000 cash or $75,000 bond.
"I was really scared," Xochil said. "I never thought this would happen to me. But I calmed down so I could remember my plan."
Meanwhile, Mutterperl scrambled to escape, trying the roof and the basement doors before stripping down to his white undershirt in an attempt to conceal his identity, witnesses said.
"My brother said, 'Is that him?' I said, 'Yes.' My brother said, 'Hold on a minute. You're not going anywhere.' Then that's when he took off," she recalled.
Neighbor Timothy Isaac, 25, Angel Garcia, and at least three others caught up to the suspect, bringing him down on the sidewalk across the street.
At first, Mutterperl, of Borough Park, Brooklyn, protested his innocence. But as they waited for cops to arrive, he changed his tune, saying, "I'm sorry, I won't do it again. I won't do it again," as the crowd pummeled him to keep him from escaping, Isaac said.
Xochil, who called for her attacker to get a stiff sentence, warned other kids to think safety first. "Try to figure out a plan before somebody tries to kidnap you. That way if somebody tries to touch you, you're ready to attack them back."