I have a maybe little stupide question, because its about a situation caused probably by my own stupidity

I started a new character a few days ago and was exping in encounters... when I reached lvl 3, I got first perk, but I didnt assign it and was exping further, and then came the moment, when I reached lvl 6 and get second perk and then I get to CHAR to deal the skill points and choose the perks, but it gave me just one perk and the second was lost...
Is this how the mechanics of the game works or is it a bug?