Hi Claudia, welcome to the community. With your musical background you already have a head start on many of skills needed to learn to play the guitar well - a good sense of rhythm, a good ear for melody and harmony and the understanding of the effort and patience needed to master any instrument, including the voice. I have never been a professional singer, if you don’t count singing for a few weddings and funerals. I did have two years of university voice training and a year of private voice coaching. I haven’t emphasized my singing as much on this site, but with your background I couldn’t resist directing you to a post I made in my log while following the singing lesson in module 19 - Steve’s singing tips
I will leave it to you to judge whether any of my tips have merit 
Also Justin has conservatory of music classical guitar training that he discusses in his lesson Flexing Time: Falling Leaf. So classical training shouldn’t be an impediment to learning the blues 
Have fun adapting your classical background to new areas of music like the blues.