I did not know (ו) could appears at the beggining of a sentence I though it was just BeiT. Every day I learn a little more.
I think you probably meant that you did not know that 'vav' can appear at the beginning of a 'word', rather than a 'sentence', as in the Hebrew word ורוד ("pink").
Good observation, by the way. That's part of the fun of language-learning: picking up on (or recognizing) new patterns. Well, if anyone doesn't it 'fun' per-se, it's part of language-learning anyway! Better get use to it! :-)
As initial וָו became prehistorically practically always יוּד (compare the variant form וָלָד (Gn 11.30) with the usual יֶ֫לֶד child), you find the letter initally mostly in borrowed loan words. וָרֹד pink is derived from the plant וֶ֫רֶד rose and is an Old Persian loan word (vrda), which entered also Europe via Greek τὸ (ϝ)ῥόδον and Latin rosa.
התה שלי זה ורוד sounds completely wrong. התה שלי הוא ורוד sounds fine, but I think suggests quite special circumstances: that it's not a one-time cup of tea that is pink, but rather a long-lived entity - maybe a brand of tea you own; and, you want to distinuigsh it from other teas.
Even when you can use it with הוא, you can just as well use it without. In the situation you probably imagine this sentence - I'm talking about the particular cup of tea in front of me - it will only sound natural without a copula.