AITA for talking about my new job at my brother's leaving dinner?

Dad asked whether I'd heard back about the interview. I said, "I got the offer this morning."

My brother Max had just finished a toast thanking everyone for coming to his leaving dinner. He's moving to another city for a job after a difficult year of short contracts. We were at our parents' house, and Mum had made his favorite meal.

I hadn't planned to announce my news there. But once Dad asked, I answered, and then kept answering. He wanted to know the role, the commute and when I'd start. Mum opened another bottle, and my aunt asked me to call my grandmother with the news.

Max smiled and congratulated me. Later, while we packed leftovers, he said he'd spent most of his own leaving dinner hearing about my new job. I said I hadn't raised the subject. He said that didn't stop me handing it back to him once I'd answered the first question.

He's right that I could have said I'd tell them more tomorrow. I was excited, though, and for once I didn't want to act as if good news had to be rationed between us.

Our parents often compare how we're doing, even when neither of us asks them to. Max says that's exactly why I should have noticed what was happening. I don't want to hide an offer, but this was an evening specifically for him. AITA for letting the conversation run?