Yes, you should definitely restart now. It's not going to take you 3 days to get to level 150, it's gonna take much more than that. What you should do is some free plays, gain some idols and gear, upgrade some talents, and only then do the objectives. Consider this: during free plays, you should restart as soon as you stop instakilling enemies. This game is not made for long runs, it's much more effective to do a lot of free plays until you are able to do objectives in a few hours, even the toughest ones (just to give you an idea of how difficult it can be, the last objective on Mugwarts campaign took me a lot of warps and buffs, and I have over 60k idols...).

Oh, final word of advice: see the minimum idol requirement for objectives? Well, multiply it by 10 (well, maybe not 10... but definitely not less than 5). Don't even try to do them as soon as you meet the prerequisite, you will end up wasting weeks and probably not even then will you finish the objective. Wait until you are much stronger than the requirement. Ideally, if an objective will require you more than half a day to complete, you are better off grind some more and try it again later.