I am currently level 12 but I can see level 1 quests on map , suddenly. Can I remove that? Or is it a bug?

This should be fixed in 3.65 - I fixed the minlevel / maxlevel fitlers.
https://github.com/AeroScripts/QuestieDev/releases/latest

Don't forget to read the readme or run the '/questie' command in game for options to customize Questie.