My mom accidentally walked inside the bathroom and caught me naked. It really freaked me out bt she told tht it's not a big deal. My dad overheard this and added tht since she gave birth to me, it doesn't really matter. My question's: r they right?

Lock the door.

I'm sure you'll be alright. Things happen.

She has seen naked more times than you can count. She even wiped your nasty butt.

If you are living with other people things like this happen.  You just need to get over it. And when you have kids and the same thing happens you will laugh at how freaked out you are about it now.

Your mum see's you as her baby all grown up, well her naked baby all grown up in this instance.  However, it's still a surprise because adults (unless coupled or nudists) don't normally see eachother in the noddy. It's a bigger deal for you because no one wants their mum seeing them naked when they are an adult especially when  it's a son with his mother, or a daughter with her father. 

Well they are right that "it really doesn't matter" .. It's inconsequential. So what if she saw you nekid by accident .. It is really NOT a big deal .. Get over it and move on.

The key is "accidentally" . . . Your privacy should still be paramount in this discussion, but since it was a little accident I wouldn't dwell on it.

Your parents are just trying to make light of it since it such a big deal to you.

Your reaction was perfectly normal.

So was your mom's and your dad's.

It's at your age and emotional development state that we humans develop "healthy" shame.

And if you develop healthy shame, it's easier to not be affected when people try to shame you for totally inappropriate reasons.

(And you will not feel any shame when you tell those people to go f*ck themselves.)