It happens... I have killed so many really cool ones I don't even wanna think about it. Very often they will not even look like something is wrong, but inside it is already mush.
The little green balls make me wanna sow some too :P I have some pods on my cacti ready to be picked. Very tempting.
Yes do it, don't let the time pass!
Right now the seeds of lophophora and ariocarpus looks fantastic, the ones of latispinus and melocactus too, even the ones of lithops that have not all germinated and I start to consider a failure, by the way I already ordered more seeds but now of astrophytum, they will take some time to arrive to my home but I hope it will be worth it, it is cheaper to have the vice of buying seeds than grown cactus haha.
And so I did it.. and that is partially your fault now :p
That's what we tell ourselves anyway