I had a lvl 29 shaman twink in TBC, they're fine, quite fun being the fastest in the BG with
https://classic.wowhead.com/spell=2645/ghost-wolf , but you're kind of forced to go the enhancement tree for
https://classic.wowhead.com/spell=16287/improved-ghost-wolf
You're still not a good FC however since you take massive damage, they're not as good as druids both when it comes to tanking nor healing. The cast is quite slow and you do not have any HotS
So I would suggest you to go for druid altho the gear is kind of whack at lvl 29