The 16-year-old came off the bench during the second half of West Brom's 3-2 loss to Wigan Athletic at the weekend to become the second youngster player in Premier League history.
"The result was disappointing – we have to learn from it and move on – but I was delighted just to get my debut in the first team," Brown is quoted as saying by the Express & Star. "It's something I've been waiting for and it's a dream come true for any young player.
"Steve Clarke kept saying 'Izzy, keep warm' and I was just waiting for the time when he said 'Izzy, get your shirt on'.
"When that happened I don't know what I was feeling. I was nervous, happy and excited – all those emotions in one. I can't describe what it was like. There is no word other than amazing."
The youngest player to feature in the English top flight is Fulham's Matthew Briggs.