Hi Pia,
I get so paranoid about my shoulders when I'm wearing anything that has straps or doesn't cover my shoulders entirely but I think in time I'll be a become more comfortable with something like that.
In fact I wish I could pull off something like that, but as Felix said, whatever makes you feel most confident. There is no point in finding an amazing dress or outfit that makes you feel 100% awkward because you won't relax, it will play on your mind and you'll inevitably draw attention to yourself.
At the same time confidence comes with being out there and doing it! If you're not sure about it yourself, maybe find something similar that will give you the same look but with some shoulder coverage (yea, kinda tricky with a dress like that

), or try other tricks that everyone uses.
Wear your hair down to help hide your shoulders. Try a nice dangley type pendant that will help draw the eyes from shoulder to your chest (assuming you're comfortable with your chest) or other accessories like bangles.
But yes, beautiful dress! Go for it!