The old advice used to be level as Enhancement until 40, respec to Ele and then add Enh or (preferably) Resto up to like 59 or 60 and then finally respec to Resto for endgame dungeons+raiding.
I’ve read lately though that some people are saying just stick with Enhancement and put points into Ele or Resto, since even if you spec Ele you’re still ultimately playing like Enhancement (pull w/Flame Shock, drop Searing Totem, autoattack until dead), so why bother to spec out of it.
Is one option better than another? Does it really matter?
Enhance is the stronger spec until level 35-40 due to long cast time for lightning bolt and chain lightning. Once you unlock the talent that reduces cast time, elemental really comes online. It still has mana issues though. You can main elemental from level 1, I did. But I wouldn’t recommend it unless you like the spec. If you just want to follow the meta, level as enhancement.
Ultimately, you should just play what you think sounds fun and don’t let other people tell you what to do. There still aren’t enough shamans to fill raids, so don’t sweat it.