No, we should not presume to give a name to a guardian angel; the reason though is not for fear of demons, but because the Church discourages such a practice:
Popular devotion to the holy angels, which is legitimate and good, can, however, also give rise to possible deviations ... [such as the] practice of assigning names to the holy angels [which] should be discouraged, except in the cases of Gabriel, Raphael, and Michael whose names are contained in holy Scripture (Directory on Popular Piety and the Liturgy 217).
By naming a creature, humans assert dominion over that creature. That is why parents have the authority to name children, animal owners have the authority to name pets, and masters once were presumed to have the authority to name slaves. But angels are pure spirits who are, by nature, superior to humans. We do not have, and should not assume, the authority to name angels. When it is necessary to address one's guardian angel in prayer, titles that denote function such as "Guardian" or "Angel" will suffice.