I can't advise you whether you should hire a paralegal or not. If they fight it you could have the ticket dismissed, or you could be convicted. Same thing if you represent yourself. The likelihood of the ticket being dismissed depends upon the merits of you specific case.
If you are convicted you will receive the points, that is non negotiable.
You could appeal to the crown to amend the ticket to a different offence that doesn't carry points. This is possible for certain offences (red light for example). I don't know for certain if this is possible with a disobey sign ticket.
With respect to some of Viper1's comments, I have to disagree. Bringing your kids to court with you will probably not affect the outcome. And they CAN convict you for just going home, because you didn't need to break the law in order to get home. The fact that your kids were hungry and you were going home doesn't really play into this scenario at all. It's not a defence, it's just the reason you weren't paying closer attention to the sign.
You have to weigh your options to determine if it's worth it for you to hire a paralegal. Cost of the paralegal vs. cost of increased insurance over the next 3 years while the ticket is on your record and taking into account the possibility that you may hire a paralegal and still get convicted. It's always a gamble.