(ABC NEWS) -- Sandy Hook parents put their children on school buses this morning and waved goodbye as the yellow bus rolled away, but this first day back since the pre-Christmas massacre is anything but normal for the families of Sandy Hook Elementary School.
Erin Milgram, the mother of a first grader and a fourth grader at Sandy Hook, told "Good Morning America" that she was going to drive behind the bus and stay with her 7-year-old Lauren for the entire school day.
"I haven't gotten that far yet, about not being with them," Milgram said. "I just need to stay with them for a while."
Today is "Opening Day" for Sandy Hook Elementary School, which is re-opening about six miles away in the former Chalk Hill school in Monroe, Conn.
Lauren was in teacher Kaitlin Roig's first grade class on Dec. 14 when gunman Adam Lanza forced his way into the school and killed 20 students and six staffers.
Roig has been hailed a hero for barricading her students in a classroom bathroom and refusing to open the door until authorities could find a key to open the door.
The 20 students killed were first-graders and the Milgrams have struggled to explain to Lauren why so many of her friends will never return to school.
"She knows her friends and she'll also see on the bus... there will be some missing on the bus," Milgram said. "We look at yearbook pictures. We try to focus on the happy times because we really don't know what we're doing."
"How could someone be so angry?" Lauren's father Eric Milgram wondered before a long pause. "We don't know."
The school has a lecture room available for parents to stay as long as they wish and they are also allowed to accompany their children to the classroom to help them adjust. Counselors will be available throughout the day for parents, staff and students, according to the school's website.
The first few days will be a delicate balancing act between assessing the children's needs and trying to get them back to a normal routine.
"We don't want to avoid memories of a trauma," Dr. Jamie Howard told "Good Morning America." "And so by getting back to school and by engaging in your routines, we're helping kids to do that, we're helping them to have a natural, healthy recovery to a trauma."
Security is paramount in everyone's mind. There is a police presence on campus and drivers of every vehicle that comes onto campus are being interviewed.
"Our goal is to make it a safe and secure learning environment for these kids to return to, and the teachers also," Monroe police Lt. Keith White said at a news conference on Wednesday.
A "state-of-the-art" security system is in place, but authorities will not go into detail about the system saying only that the school will probably be "the safest school in America."
Every adult in the school who is not immediately recognizable will be required to wear a badge as identification, parent and school volunteer Karen Dryer told ABCNews.com.
"They want to know exactly who you are at sight, whether or not you should be there," Dryer said.
Despite the precautions and preparations, parents will still be coping with the anxiety of parting with their children.
"Rationally, something like this is a very improbable event, but that still doesn't change the emotional side of the way you feel," Eric Milgram said.
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