she is very cute

(yes, im another european member)
i recommend moving the water to the cool side instead of the basking spot. as with all other food, bacteria and algae grows quicker when the temps rise (to a certain temp, at which they die xD)
there is no way to know if shes male or female at her age. when she is fully grown, take a photo of her from above and the members here can guess. otherwise theres only two ways of knowing which gender it is, either by finding sperm plugs (males sometimes but not always drop them), or by observing their behaviour when they are with another skink. i do not recommend the last mentioned since it can be very dangerous to attempt.
nice to see someone from spain. apart from at the zoos ive visited and some reptile shows on teneriffe, ive never met anyone in spain owning or even talking about captive reptiles. Por supuesto, he visto muchísimos lagartos en la naturaleza allí.
my spanish skills are more than rusty.