How long does nepenthes attenboroughii seedling take to reach adulthood?

[Hechtioides]

I have seed sprouts of nepenthes attenboroughii. How long does it take for it to grow to adulthood?

 

[Grey Moss]

How sure are you that those are atten? The seed for that species have never been available on the general market. All the atten seed sold previously have been swaps with other more common species or poached from the wild. Either way, it would be 5 plus years before those would be anywhere close to mature if they are really atten.