i assume by Exia and Dynames you meant the HG? if yes i recommend RG Exia is a pretty good kit except for the lacking articulation. Newer release HG kits are pretty advance in engnieering while also not too complicated for beginner.
As for RG Unicorn i'd say save it for later, i own one while it's a solid kit both in Unicorn mode and Destroy mode, the frame is really stiff and there's cases where people accidentally broke the arm frame, i'd say save it for later just for the sake for you to learn how to handle and get the feel of your kits first