Unlike the (human) OP in another similar thread, I'd get the new loner
a buddy ASAP.

HTH

--Karen D.

We are going through this at the moment, although with an older cat.
Henry and Gloria were 9 last year when Henry had to be put to sleep
unexpectedly - a year ago today :-(   -because of a heart problem and
thrombosis.

We had been looking for a pair of kittens since April, but there aren't
a lot available (owing to neutering).  Anyway, we found a pair of
delightful B&W kittens at the beginning of September.

I have to say, life has been quite difficult since then.  Gloria has not
taken to these kittens at all, but they love her to bits.  We now have
to feed her on the tall dresser in our bedroom, since she won't go into
any room they're in if she can help it.  She spends most nights outside
unless I can entice her in, when she is happy sleeping in the bedroom.

The kittens are locked in a downstairs room overnight, but now they are
at the age when they can go out, so they will invade her garden.  Who
knows what will happen?

We made the decision to get kittens because Gloria sank into a deep
depression following Henry's death. Now she's not depressed, she's
anxious instead.  But things are getting better.  She does touch noses
with them if they are held up to her. BUT - they must not be higher than
her!

I'd say take a chance and get another kitten.

s.