What is my degree if I am still a bachelor student?
In the US system, I would advise to leave it blank. But in some European education systems (and in particular with the impetus of the Bologna process), the high-school diploma is considered a formal degree. In France, it is called baccalauréat, in the UK it's the A levels, in Spain (you seem to be Spanish) it's the bachillerato.

So, if you are in a European system, I would advise you to write bachillerato/*baccalauréat*/A-levels, otherwise leave blank.