I was wondering whether you might be able to get to lounge from your seat somehow, by mentioning to whoever is 'on guard' that your 13 year old is in there.
I wonder if they'll be a final sales period only available to those who have been to every home and away game since 1967 and who have made 25+ appearances for CCFC reserves or higher.
but only for tickets in blocks 11 and 12 (according to website)
https://www.ccfc.co.uk/news/2023/may/tickets-blocks-11-and-12-to-be-available-to-sky-blues-fans-for-play-off-semi-final/
Website says "For children under 12 years, the dress code is relaxed", so would seem to be fine, although looks like tickets are full price:
https://www.ccfc.co.uk/news/2023/may/news-hospitality-available-to-book-for-play-off-semi-final/