If boys reach the first row before older people, they are more entitled to it
Question

                Some children come early on Fridays, then people who are older than them come and make them get up, then they sit in their places. They quote as evidence in support of this the hadeeth of the Prophet (peace and blessings of Allaah be upon him): “Let there be behind me those among you who are wise and mature.” Is this permissible?
Praise be to Allah. 
          This is the view of some scholars, who say that it is 
          better for young boys to form rows behind the men. But this opinion 
          is subject to dispute. The more correct view is that if they get there 
          first, it is not permissible to make them sit further back. If they 
          reach the first or second row first, those who come after them should 
          not make them sit further back, because they got there first and that 
          gives them the right over those who did not get there first. So it is 
          not permissible to make them sit further back, because of the general 
          meaning of the ahaadeeth concerning this matter, and because making 
          them sit further back would put them off coming to the prayer and from 
          competing in that – and this is not appropriate. 
 
          But if a group of people arrive together, because they 
          are traveling together or for some other reason, then the men should 
          form the first rows, the boys behind them, and the women – if there 
          are women present – should form rows behind them. This is when a group 
          is all together. But for older people who come later to make the youngsters 
          move and then take their places is not permissible, as we have mentioned. 
 
          With regard to the hadeeth of the Prophet 
          
          (peace and blessings of Allaah be upon him): “Let there be behind me 
          those among you who are wise and mature” – this is meant to encourage 
          people who are wise and mature to hasten to the prayer and to be in 
          the forefront of the people. It does not mean that those who arrived 
          before them should be made to move for them, because that goes against 
          the shar’i evidence that we have mentioned.