I would only recommend mining if this is on your main account and one you play seriously. If you want it to be on a botting account I would suggest having herb/mining or engineer instead of one of the two. If you want a char so it is a crafter I would suggest alchemy along with jewelcrafting.
Not counting any racial or other bonuses, at a skill level of 350 you can learn the Grand Master stage and gain up to a maximum of 450 points: Gathering professions have a minimum level of 55 to become a Grand Master. Crafting professions have a minimum level of 65 to become a Grand Master.