The Newcastle defender is being supported by his mother, cousin and grandparents in Croatia - and so far he's played in both games as the Young Lions have made it two wins out of two.
Steve Cooper's side are on course for a place in the quarter-finals, and victory over the Netherlands in Zapresic on Wednesday would see them top Group D.
And, speaking to TheFA.com, 16-year-old Gibson said: "I have to admit that I got a bit emotional when I saw my family in the stand, particularly seeing my grandma and granddad because I've always wanted to do well for them.
"I wanted them to see me play for England and now they've done that. Seeing them in the crowd was nice but when they were getting a bit emotional it soon hit home that I had to focus on the game."
Stanley-born Gibson - whose older brother Liam is also on Newcastle's books - was a regular during England's qualifying campaign but admitted: "Everything has been building up to this moment since the start of the season.
"When you arrive, get together as a squad and see those familiar faces then it's just business as usual but when I pulled on that England shirt with my name on the back for the first time then it was just an unbelievable feeling.
"Seeing your name on the back of the shirt is what you dream of as a kid. It's been an unbelievable start for us and we just need to carry this on."