Experian's free account lets you sort (two lists, one open cards, one closed cards) by date opened, and that makes it easier to figure out your ?/24 than on Credit Karma which used to let you sort but no longer does.

OTOH, Experian has bug where it claims every card was opened on the 1st of the month, so you must go to Credit Karma to find out the exact open date if it matters to you. (If you're definitely 3/24 or 8/24, it probably doesn't matter. If you just turned 4/24 this month, it may matter. OTOH, using Experian's date gives you the "worst case" of how Chase could possibly handle it, so maybe that's not so bad after all?)

Having said that, that's the way Chase counts 5/24 (cards showing your credit report, open or closed, with an "opened on" date in the past 24 months). BofA could count open and closed cards differently. It could even look at how long you keep cards open! And as mentioned, it could consider oodles of other factors, like your BofA history (in unknown ways). It's going to really hard for everyone to document all of the things that BofA could count.

For example, I got a Choice BofA card years ago when they were issuing them, and I've kept it for years longer after they dropped CHoice and converted it into a useless card. Does BofA like me better because I've kept one card open with them for many years (despite hardly using it, except for "flashing it" for Museums on Us )? (I don't see how it can hurt, but I can't tell for sure if it helps.)