Minecraft enchant luck with the Picaxe?

I have crafted a magic table, and wanted to enchant with this, luck on my pickaxe. However, when I put the pickaxe on the Enchantment Table, I always get the same enchantments (Effiziens 2, Shelf life 3 and Shelf life 4 or so). So what conditions must be met so that I can enchant luck on my pickaxe, or how can I change the enchantments the magic table suggests to me in the magic table?

They are always the same, until you enchant something.

So if you have z.b. Enchanting a book changes the enchantments that you can put on your items.

With luck you can then draw luck on the picaxt

Many thanks.