Doesn't make sense to buy a bike with immediate desire to upgrade.
105 is regarded as a "best bang for buck" component group.
Ultegra won't help you ride faster or farther.
I can appreciate you wanting to make the right choice, but you can
also strangle yourself agonizing over the choices.
If one of them really fits you and you like the ride, then get it and
get on the road.

S