Twins Julia and Jessica Mauer photographed with their little brother Isaiah Luke from their reunion Monday night in Aurora, Colorado.

"It felt like we hadn't missed a beat!" Julia Mauer told ABC News of her long awaited reunion with her baby brother, Isaiah Luke.

Mauer, 24, found her brother Isaiah, 19, earlier this month after posting a Facebook plea for help. The two finally had their reunion in person on Monday night.

"Our reunion was absolutely wonderful!" Mauer said of their tearful meeting that was full of hugs and reminiscing about old times.

Mauer, accompanied by her twin sister Jessica, met with Isaiah at his fathers' house in Aurora, Colo. "His fathers were very welcoming and supportive," Mauer said. The trio talked for hours and the sisters stayed for dinner as well. "It was all very natural and easy going," Mauer said.

The brother and sister, who are half siblings, were separated when she was 12 and he was 5 after they were taken from an abusive home and placed with different grandparents. Isaiah was later adopted by a family and Mauer lost contact with him.

With only a description and the sweet memories of her brother to go by, Mauer scoured high school yearbooks and athletic rosters to find Isaiah. Earlier this month she posted a plea on Facebook saying, "I have a little brother named Isaiah Luke who has been missing from my life for the past 12 1/2 years," along with a birth date and a detailed description of what he looks like.

The next day, a tip led her to her brother and on Monday they finally met again in person and Mauer finally got to see those "bright blue marble-like eyes" again.

With more than 12 years to catch up on, "conversation flowed and it was a very enjoyable night," Mauer told ABC News in a Facebook message.

"I can never explain what this has meant to me!" Mauer said she felt "so blessed to have gotten the opportunity to reunite" with her brother. Stepping quickly back into the role of big sister, Mauer gloats, "Isaiah is a wonderful young man."

Mauer has told ABC News that they still want to find a younger sister named Sarah who was also adopted, but will wait until she turns 18 before trying to locate her.