It is stipulated that the mahram who is going to travel with a woman should be an adult
Question

                I have been through the website and read the things you wrote about women traveling without a mahram, and i have taken the decision that i will never travel again without a mahram. May Allah (swt) make me steadast in my words. I couldnt find any answer to my question on the website.

My problem is that, my father never travels with us, and i dont know when Allah will grant me with a good husband. Can i travel with my little brother who's 13 yrs old as my mahram? he is the only male mahram i have at this moment, apart from my dad. how old should a mahram be, when it comes to women travelling? what do i do, i can never see my family members back in my country and other parts of europe, if i can't travel. is there any solution for people in such situations like me. i have told my family that it's haram for a women to travel alone without a mahram, but they are not taking it serious, because poeple back in my country (gambia) don't know much about it.

I'm really looking foward for your answer to my question and May Allah bless you for all the good job you are doing on the site.
Praise be to Allah.
    What is required of the Muslim is to obey the commands of 
    Allah and not pay any attention to what people say. Allah, may He be 
    exalted, says (interpretation of the meaning):

    “It is not for a believer, man or woman, when Allah and 
    His Messenger have decreed a matter that they should have any option in 
    their decision. And whoever disobeys Allah and His Messenger, he has indeed 
    strayed in a plain error”

    [al-Ahzaab 33:36]. 

    Your resolve to obey Allah and follow His commands is to be 
    appreciated, and we ask Allah to increase you in guidance. 

    Secondly: 

    It is stipulated that the mahram who is going to travel with 
    a woman should be an adult, because the purpose of having a mahram with her 
    is to look after the woman and protect her, and this cannot be done by the 
    one who is not yet adult. 

    Shaykh Ibn Baaz (may Allah have mercy on him) was asked: What 
    is the minimum age for a youth to be a mahram for a woman if she wants to 
    travel? 

    He replied: 

    The minimum age for a man to be a mahram for a woman is 
    puberty, which is when a boy reaches the age of fifteen years, or maniy is 
    emitted with desire, or coarse hair grows around the private part. 

    If one of these three signs is present, the male is now 
    regarded as accountable as it is permissible for him to be a mahram for the 
    woman. 

    End quote from Majmoo‘ al-Fataawa, 16/382 

    And Allah knows best.