Is it considered lying or an imitation of men for a girl to write false information about herself in forums and use neutral names or sometimes speak as a male to protect herself, taking into account her justification that changing her name and age is not considered lying? And what is the legitimate alternative if that is forbidden?

The basic rule concerning lying is that it is forbidden, and it is only permissible when there is a necessity, such as realizing a benefit or averting harm. Changing one's name is permissible, as long as it does not involve impersonating a different gender. Impersonating a person of the opposite gender in forums by changing expressions, words, and pronouns is not permissible, because it is a forbidden lie and contains greater harms; it is deception and temptation, and it falls under the category of imitation (tashabbuh) which is forbidden by religious law, as the Messenger of Allah, peace and blessings be upon him, cursed those men who imitate women and those women who imitate men. Changing one's age is not permissible because it is a lie, but it is permissible when there is a need, by using equivocation (tawriya) and allusions (ma'areedh).