target mini nicotine 12mg 6mg 0.6mg lower higher

I bought a target mini and the young guy there tolg me I should never go over 0.6 or at the most 6mg nicotine. I started vaping about 6 months ago to stop smoking and LOVE my target, but is it going to make me sick to go up to 12mg? I dont feel like Im getting enough nicotine, but Im not an...