Starting christmas Christmas in November!
Here in Costa Rica everything smells like Christmas [you must use a subject for your verb] and most of the stores are selling gifts and decorations for homes houses [I think it sounds better, but I suppose you can use either word]. This is a little bit annoying because it is very precipitate premature, since we are just starting at the beginning of November!
by the way On the other hand, it is nice to think that we are almost on vacations the holidays will start soon!
[In this last sentence, you are saying something that is almost the opposite of the previous one: this is a bit annoying... it's nice to think. If you want to express contrast, you should use On the other hand or However, but definitely not "By the way"]

Some corrections I'm not really sure about:

The title feels wrong somehow, because I think it should really begin with a noun, not a participle.

Maybe "Christmas starts in November!"?

"This is a little bit annoying because it is": you're actually expressing an opinion, so I think it should be more like "This is a little bit annoying because it feels". What you did is not wrong grammatically, but i believe that this is the right way to write it.

I hope this helped!