Best path for reteaching myself Math through Highschool level.

Hi, I always wanted to work in the science field and finally woke up to follow my dream, however my math has ALWAYS suffered fatally throughout my entire education, I can do the basics like add/sub/multi/divide no problem, but anything beyond that has always been like another language to me.  

I started learning fractions etc on Khan and so far to my surprise the subject I once hated has now become my long lost love.

My question (sorry for the long back story) is whats the best route to relearn math from a fresh perspective?

I am at this moment finishing up the 4th grade course and just wondering if I should obviously continue it until the 8th grade mark, then move onto the high-school course?  I've read about some courses not being fully updated, but Ive found no new posts about that so Im just wondering if the high-school course is good to go on to after or if I should mess around in more specific branches or math?  

Just wanting to do this right and not waste any time! ^_^  TY for any help!

P.S if you have any other tips for my journey they would be appreciated!