Depends on how “novice” you are, if you have a place to work on it, have a buddy that can drive you back and forth to the parts stores and how many tools you have access to or are willing to buy to get the job done. All DIY’ers had to start somewhere on some project and we all had a “first time” for any task we’ve done (I’m still doing first times on various things)
A head gasket can be a bit daunting to the novice especially the timing chain (or belt). Getting it properly re-installed on some cars can be a bit of a challenge. I’d hit YouTube and see if anybody has videoed their head gasket change or head removal on a Rav 4 or similar Toyota and then you can get a good feel for whether or not you can handle the job yourself.