Classic is retail worth wasting my time on or should i be playing classicm

So ive always been super into wow, but for a while my mom didnt have money for internet so i could never play. Now im in college and i have internet and im OVERJOYED that i can play wow again. However, im not completely up to date with the current state of affairs. One of my favorite parts of leveling was experiencing all the different xpacs while leveling and almodt givinfbyour character history from it. Now, i HATE this new system where its 1-50 and u can normally only go through 1 or 2 xpacs per leveling experience (and its out of order which isnt as immersive). Thing is though, i also enjoyed raiding and mythic dungeons in legion, and i would like to get back into that stuff that is really at its peak innretail wow. So i guess my question is, what is worth playing more right now? Retail or classic(tbc and now wrotlk). As a busy college student with a compsci major and a minor in math as well as workinf at lowes, i only have time to really get into one so which one should i play (or play first at least) via /r/wow https://ift.tt/W0XGQR6