Last name help!!

So my son will be 1 tomorrow

His father and I broke up when I was 7ish weeks pregnant (we knew from about 5 weeks, relationship broke down due to his infidelity and not being able to grow up, he's now 27 and I'm 23) anyway... He ran away and had absolutely nothing to do with me throughout my pregnancy..when my son was delivered I contacted him and let him know baby was born and let him visit, he visited with his parents and signed the birth certificate. On the birth certificate showed I had given my son my last name, he had no complaints with it at the time. He was in and it of my sons life and then decided to take me to court, we went to outside mediation and set up and agreement for which he decided not to do eventually and decided to take me back to court. We were sent to court led mediation and we once again came up to an agreement, this agreement he hasn't been doing, he's barely been there for my son and in this mediation he decided he wanted to change my sons last name to his, I agreed to think about it then decided I didn't want to change it, I'm the only one that's been a constant in my sons life, I've been told by his father that he doesn't want anything to do with him and we came to an agreement that our son can decide if he would like to change his own last name when he's old enough. Well contact has broken again I got in contact with my lawyer about how slack he's being so he's decided to take me to court. He's now trying to get full custody (hahaha) anyway he's abandoned contact again and pushing to get my sons last name changed to his..I've found out that the judge can rule against this and decide to change it so....can anyone tell me why kids are typically given their fathers last name? And has anyone been through this and can give me some advice??

From what I understand if your not married or have not changed your name, unless specified at the time the child's last name will always default to the mothers last name. It's just automatic.
From the history you have just gave and the fact a year has almost gone by I would find it highly unusual for a judge to rule to change the last name. I'm only in my first three years of practice so please don't take this as legal advice but I wouldn't stress too much about the name change if what you have said is accurate :)

As you said if your son felt strongly about this down the track he could change it with your help or if old enough on his own.

Hi there I have been through the court system and dealt with a dead beat dad and believe me it won't change I fought and gt sole custody and after I got that he wasn't seen nor heard from again . I have my boys with a high finated last name with my last name first then the fathers last name which I got told to do as legally my last name being first gives me more right and the option my boys could choose when they are older . What ur ex is trying to do is get you to drop your name so his last name can be on certificate giving him more rights. Don't change it . Hope this helps.