4 1/2 month old Siamese in heat??

I have a 4 1/2 month old might be 4 months and 3 weeks but for sure no older.( papers are in the cedar chest to late to dig them out) Today she has been walking around Howling at the top of her lungs as only a siamese kitty can do. Off and on all day. Shes not showing any other signs of being in heat just this yowling like females do when they go in heat..
For sure shes not sick because shes being very rambuncious and playfull with the older cats.. Could she being going in heat this young?? Shes going down in the finished basement and yowling, as soon as any of the older cats go down and run around and play shes stops yowling. The other 5 cats are spayed/neutered of course as she will be. I usually have them fixed at around 6 months. Shes so little I hate to have her spayed yet. Could she be in heat?

I believe that it is possible; the Siamese breed is known for maturing sexually at an early age.

Sorry, I also meant to congratulate you on your new(ish) addition. I have two Siamese myself, although they're both boys, so I have no personal experience with early heats in cats!

Oh yes, heat is possible as early as four months. Not common but possible. I hope you can catch her between cycles and get her spayed quickly.

Shes in heat for sure showing all the other signs today. I will have to get her in to the vets and spayed as soon as she goes out of heat. Shes tiny and I know its riskier to spay when in heat so due to her age, size and weight I'm going to wait till shes out of heat then in she will go.

While in heat a bit riskier yes but size and age not much at all! I get my kittens done as early as I can-had 7 done at 8 and 9 weeks old-they came home basically wanting to get out of carriers to play! They bounce back much faster. I have had some done right after a heat at 5/6 months old and no issues.

Mooch went into heat at 4 months old. I believe it was just a day or maybe 2 before her spay appointment! I had scheduled it like a month earlier too! Noodles kept looking at her like she was nuts! LOL!

ETA: I think a first heat is sometimes a shorter one. Not sure on that; but I think I heard something like that. Mooch's didn't seem to last more than a day; or I just missed it from being at work during the day.

Most modern vets will do a spay as long as the kittie is 2 lbs.

Yeah, Dot went into heat at 16 weeks, 3 days before her scheduled spay! My vet made me wait 10 days before spaying her, he said she would be out of active heat at that point. If you wait too long, she'll go right back into heat again, so 10 days from now would probably be your best bet, too. However, I have spoken to other vets who say that they don't mind an in-heat cat spay at all, that it's not much riskier for them (unlike dogs) and not much harder to do. So it depends on your vet's preferences.

If she's healthy, size isn't really a factor. As long as she weighs at least 2 pounds, there's no real difference.