The real skill speed is pretty fine. I rerolled after the patch, and after less than two hours skills like Agility and Sprinting are already maxed, I also maxed cooking and I'm already reading Long Bow crafting. After about ten skinned walkers the lores Bone Tissue and Emalj are already maxed. Other material lore especially for alchemy and cooking will be much harder.
The annoying part will be the clade gifts! Currently we get 10 clade gift points with character creating, but @FarmerJoe answered my question in the Discord channel and we will probably get no clade gift points at release. I don't know how many walkers have to be killed for the first point, put from level 10 to 11 the number of points is 880 means 176 walkers (one walker gives currently 5 points). Clade gifts are something for long term players only. I can't estimate how long it will take after release for the first player to reach all 20 points, maybe a year or more.