mamashtakah -Yes, she is serving Israel -she isn’t serving Hashem.
The purpose of e/o is to serve Hashem and Israel is Not in place of G-d. Lest you think that this is my opinion in general about going to the Israeli army – perhaps it is. But I wouldn’t castigate anyone (male) who decided to join because there are Gedolim who held it was/is Mutter. There is NO excuse or HETER for a female to join the Israeli army, even though they say it’s good for morale.