Yes... You can take an estimated guess. But it'd be hard to make an exact age.
ask it!
After they are about 3 weeks old. I just got a new baby kitten.
They will be bigger with more spots on the shell. Usually you can tell just by looking at it.
A kitten can grow up fast or slow and many breeds stay a kitten for just one year or may do for a little longer or shorter. Ragdolls do not reach full growth until 4 years.
There's no telling. If you rub something your old cat lies on onto the kitten, the kitten might be accepted. Good luck!
by the smell
The best way to tell what gender a cat is, is by looking underneath the base of its tail. A male kitten that has not been neutered will have two furry testicles right below the anus, and a penis right below the testicles. A neutered male cat or very young kitten will not have visible testicles, but there will be a noticeable space between its anus and penis. Spayed and intact female kittens alike will have a genital opening (vulva) which is often seen as a tear-drop shape located right below the anus. It is usually very difficult to accurately tell the sex of a kitten until it is at the very least two weeks old. In males, the testicles do not begin to develop until four to six weeks old.
there are spacial kitten foods.
it is sooo old that its just old thank you from looking at this
If the kitten ate it willingly, nothing bad should happen. A 4 week old kitten is just at the very earliest stages of weaning, so don't start feeding it solid food only at this point, he/she still needs to nurse regularly.
Yes she can go through depression. To get over this, adopt a new friend for her and show her you love her
I myself, being the owner of many cats, can tell you this. Your cat may or may not accept your new kitten. The only thing you can do is just introduce them slowly, don't force anything onto your older cat that it doesn't want. The older cat will at first hiss, cuff, or growl at your new kitten, but in time he'll learn to tolerate the newcomer. He just needs to learn that the kitten isn't there to take his place, make sure you're still giving your older cat the attention that he wants and show him that even though you have another cat, you still love him just as much.