Democrats need to understand something: WE DON'T CARE ABOUT THE UNFORTUNATE BASTARDS WHO ARE CRASHING THE BORDERS, REGARDLESS OF THEIR AGE.
We care about the 330 or so million people who are living in the country legally. The people who are paying taxes to support, feed, educate, and care for these border-crashers (and don't call them IMMIGRANTS! They are NOT IMMIGRANTS!). The people who are sending their kids to schools that have to waste their time teaching the children of border crashers who don't speak English, and will depress the education for everyone around them for as long as they attend. The people whose jobs are taken by border crashers who are willing to work for less, and for whom payroll taxes are an option to their employer.
If you think that sympathy for these border crashers is a winning issue for the misfit who eventually leads the 2020 Democrat ticket, then more power to you. But you need to consider whether you are paying too much attention to the people in your particular echo chamber. It is not reflective of reality. Political or otherwise.