Noah Pozner and Jack Pinto, both 6, were the first laid to rest.
"Today is extremely emotional," Noah's aunt, Victoria Haller, tells PEOPLE. "My sister-in-law has been pretty much a wreck, which you can imagine. It's the worst thing in the world to lose a child."
Pozner, a loving boy who was inseparable from his siblings, had his services at Abraham L. Green and Son Funeral Home in Farfield, Conn., with his burial at B'nai Israel Cemetery in Monroe, Conn.
The entrance to the funeral home was adorned with white balloons. A large oak tree across from the home was covered with a sign that says, "Our hearts are with you Noah."
Pozner's twin sister, Arielle, along with older sister Sophia, 8, both survived the shooting.
Pinto, known for his love of the New York Giants, had his services at Honan Funeral Home in Newtown, and his burial at Newtown Village Cemetery.
On Saturday, his favorite player – wide receiver Victor Cruz – dedicated his game to Pinto, writing, "Jack Pinto, My Hero" on one of his cleats, and "Jack Pinto This one is 4 U!" on his gloves.
Friday morning's massacre took the lives of 20 children – 12 girls and eight boys. The gunman, identified as 20-year-old Adam Lanza, took his own life. His mother was also found killed in a different location.
Sandy Hook was closed on Monday. Other schools in the area will open on Tuesday, and the district has reportedly made plans to send surviving Sandy Hook students to a school in a neighboring town, but there is no date set.
Other victims of the tragedy have funeral dates set for later this week.
Reporting by MARY GREEN