Once in a Lifetime Band Concert vs Son's Birthday Celebration

Here's my dilemma. There's a boy band concert that’s probably on their last tour because it's their 25th anniversary. It falls on the same day as my son's birthday. What do I do?

In my head, I'm thinking I could do both because my son asked to go to a theme park, which is a daytime thing, and the concert's at night time.

But then there's that awkward gap because the theme park closes at 6 PM, and the concert starts at 8 PM, so it would be a rush in between the two. It takes about an hour to go from either location to our house so it would be literally wheels off at 6 PM at the waterpark and 5 minutes at home for a quick change then back out again. Sounds do-able, except our family tends to be one of the last ones to leave the theme park (its never enough for our little lion).

I thought about bringing him along to the concert so we can just go straight, but he will be very tired and honestly speaking, if this concert is a once in a lifetime thing I don't really want him to ruin it. It won't be his fault of course, as a parent I do take responsibility for his physiology so if he's in a mood often its because he's not rested or hasn't eaten properly and that's my fault.

I could end the theme park visit earlier or go to the concert a bit later if I don’t want to rush either one...

When I asked my husband about it, he said, 'Well, your son's birthday comes every year, but this concert is probably only once.' And I thought, yeah, it's so true, but it feels so selfish. I was thinking, even if we spend a whole day out together as a family and then I head to the concert, I wonder if my son would think, 'Oh, I see, on my birthday, you decided to go to a concert,' like I’d just leave him with a babysitter.

You know how children sometimes only remember the 'bad' thing? Even if they've had a whole day of everything they want, they might focus on being with a babysitter for those three hours, instead of the ten hours of fun. I'm such in a dilemma.

What would you do if your favorite band's final concert is on the same day as your son's birthday?