A 60+ couple messaged us and I need help phrasing my hesitation without sounding like an ageist asshole

ok this is uncomfortable to type but I'm gonna try and be honest. me 38, dh 41, in the LS about 3 yrs. we got a very warm, very well written msg yesterday from a couple who are 62/65 and have been in the lifestyle since the 90s apparently. their profile is lovely, photos are recent and respectful, no weird stuff. and my gut response was... hesitation. and now I'm sat with the hesitation trying to figure out if its something real or if its just internalised ageism that I need to shake off. bc heres the thing. I dont have a hard "no" on age. weve played with a couple in their late 50s before and it was great. but theres something about the jump to 60s that pinged in my head and I cant tell if its bc of attraction stuff or if its bc i've absorbed some weird cultural baggage about what "playing" should look like. dh and I talked about it last night and he said "if you're not into it just say no, you're allowed to have a type". which is true. but I also dont want to ghost lovely ppl, and if I do reply I dont want my reply to read like "youre too old" bc thats horrible and also not exactly accurate. the actual feeling is fuzzier than that. how have ppl handled this. is there a kind way to say "we're probably not the right match age wise" that doesnt land like a slap. or do you just send a polite generic decline and not get into the reason. i genuinely want to do this right.