Is there an age at which a woman no longer needs a mahram?
Question

                I am a single woman aged 38. I am a teacher and I have not got married yet. My father has passed away, and I help my mother to some extent with household expenses. I want to perform Hajj, and my name was drawn in the “lottery” (to select who can go for Hajj) but I need a mahram. My brother does not have enough money to spend on his own expenses. I know that I should pay for him, but I need the money for my future needs. So I have decided to delay this obligatory duty until I reach an age when I no longer need a mahram. Will I punished for my decision? I hope you can answer me because I am very anxious.
Praise be to Allah.
      Firstly: 

    Hajj is only obligatory for those who are able to do it, 
    because Allaah says (interpretation of the meaning): 
“And Hajj (pilgrimage to 
    Makkah) to the House (Ka‘bah) is a duty that mankind owes to Allaah, those 
    who can afford the expenses”

    [Aal ‘Imraan 3:97]

    One of the conditions of being able to do it for a woman is 
    that she should have a mahram who agrees to go with her. If she cannot find 
    a mahram then she is not obliged to perform Hajj. 

    It says in Fataawa al-Lajnah al-Daa’imah (11/93): One 
    of the conditions of Hajj being obligatory is that one should be able to do 
    it, which includes having a mahram for women. If a woman does not have a 
    mahram then she is not permitted to travel, and she is not obliged to 
    perform Hajj unless she has a mahram and he agrees to travel with her. 
    Allaah says (interpretation of the meaning): 
“And Hajj (pilgrimage to 
    Makkah) to the House (Ka‘bah) is a duty that mankind owes to Allaah, those 
    who can afford the expenses”

    [Aal ‘Imraan 3:97]

    See also questions no. 316,
    5207 and
    34380. 

    Secondly: 

    There is no age at which a woman does not need a mahram, 
    rather at all ages of her life after she reaches puberty it is not 
    permissible for her to travel without a mahram. No distinction is made 
    between young women and old women, because the Prophet  (peace and 
    blessings of Allaah be upon him) said: “No woman should travel except with a 
    mahram.” Narrated by al-Bukhaari and Muslim. 

    We have explained this in the answers to questions no.
    47029 and
    25841. 

    Thirdly: 

    If a woman has a mahram, she has to spend on him.  

    Ibn Qudaamah (may Allaah have mercy on him) said: 

    She has to spend on her mahram’s expenses during Hajj, as was 
    stated by Ahmad, because this is part of her being able to perform Hajj. So 
    she has to spend on his expenses such as travel. Based on this, part of her 
    ability to perform Hajj is that she should be able to afford provisions and 
    travel expenses for herself and for her mahram. 

    Al-Mughni, 3/99 

    Al-Sarkhasi said: 
If a mahram travels with 
    her then she should spend on him from her own wealth. 

    Al-Mabsoot, 4/163 

    Fourthly: 

    With regard to your delaying Hajj because you need the money, 
    please see question no. (11534). 

    And Allaah knows best.