I'm 14 years old I'm turning 15 this year in December and I want to get my tongue pieced without my mom knowing how do I do it

You have to have parental consent to have it done under the age of 18.

I am not even sure what a tongue "piecing" is...

But, if I am right, I believe you are asking how to get your tongue pierced without your mother knowing. And as mentioned above, you have to have parent consent in the U.S to get a body piercing. Also you will not be able to hide it from anyone. Your tongue will swell and hurt. You will not want to eat and you won't talk properly for a while. If you do not take care of the piercing it will become infected and then you would most defiantly have no choice but to tell your mom.

My advice to you, wait until you are old enough to spell what you want and until you are not afraid of what will happen if your mom finds out that you did it. :)

This is not something to try to do yourself. Your mouth is full of bacteria and it will certainly get infected. You could end up without a tongue... Yes, it could have to be removed. When you are 18, fully self supporting (no money or housing or other help from home) you can have a professional do it properly.

That said, you probably aren't old enough to know tongue piercings in girls have strong sexual connotations and you will come off as a slutty girl to a great many people if you do this. Bad idea. And how long you suppose it would be before you have to go to the dentist or get a strep test, or you just talk in front of your mom? She'll make you take it out and it will be a dumb waste of pain, money and trust.