This from an article from the Valley Press last November when Estes signed with Long Beach State.

"Estes started out as a catcher when he first started playing baseball as a 4-year-old. He started pitching and catching when he was about 6 or 7 years old.
“I’ve been pitching ever since,” Estes said. “But, competitively, freshman year. That’s when I took it serious.”
Entering high school was when Estes really started to hone his talent as a pitcher.
“I thank God for my gift when I was younger, because it got me through because of how hard I threw,” he said. “I just threw the ball, there was really no (technique).
“But as soon as I came in here freshman year, I had guys like Griffin Hagen —I’ve known him my whole life — he took me under his wings and taught me a lot of things.”
Estes said he threw consistently at 77-81 mph as a freshman, topping off at 83 mph. He pitched 26.2 innings in nine appearances (three starts) and posted a 1.05 ERA with 31 strikeouts and 16 walks.
After working with Hagen and Paraclete pitching coach Mike Fullmer, he upped his speed, topping out at 94 mph in a big playoff game against Righetti his sophomore year.
Estes finished that season with a 0.31 ERA and 9-1 record. He pitched in 15 appearances, 12 starts, with five complete games. In his 90 innings pitched, he allowed 35 walks and struck out 97 batters, allowing just four extra-base hits, all doubles.
That’s when he really started getting the attention of college coaches. Estes posted another sub-2.00 ERA in his junior year."