Sorry honey, but your therapist is right.
Putting yourself first helps protect your health. Moms have a tendency to give and give and give until they don't even know where THEY end and their kids start. That's not a healthy thing. Moms who go overboard with this tend to allow their children to take advantage of them and excuse away the behavior. That's not good for the kids either.
We've seen moms on here whose teens and adult children pull away from them so much that the moms are totally miserable. Most of the time it's normal separation. Sometimes the separation is because the kids feel suffocated by the mom and won't have much of a relationship. It nearly kills the mom because all she can identify with is her status of being a mom and, with her child gone, she doesn't know how to just be her instead of just being a mom.
It may seem like to you that this isn't something you should worry about this early. But this is a mindset, mom. I will bet that your therapist sees this in you and is trying to help you understand this in order to keep from being that kind of mom in a few short years. Kind of like the analogy of the airplane directive that you put your own oxygen mask on before you assist your children, you need to take care of yourself as a woman first before you take care of your kids. Being able to do this will help you be a better mom in the long run, as well as have children who grow up understanding that they aren't the center of the world.
I can't speak to the idea of it being important to have a connection with your therapist from personal experience, but I would think that sometimes we need someone giving us advice who doesn't sugarcoat and affirm everything we do. Personally, I don't think I'd want my therapist to be my friend. You might consider that in regards to your new therapist.