You own a family business. For your child's entire life, you have assumed they would take over that business. They're counting on it. Do you just want to get them a job at the company as soon as you can?
Naturally, this is a personal decision that your family needs to make. There is value in experience and working with your child -- rather than just giving them the company when you retire or pass away -- can help them tremendously.
However, there is value in having them work outside of the family business, as well. Some parents have even told their children they won't consider them to take over the company until they prove they can succeed at another company.
The problem is that your child has job security at your company, due to their last name, and they know it. They may not take the job seriously. They may not work as hard. Even if they think they're working as hard, they know in the back of their mind that they're not going to get fired.
If you make them go out and get another job, they learn what it's really like when nothing is guaranteed. It's a different work experience, and really, it's a growing experience. They'll learn things at that job that you could never teach them. When it's time, they can then come home and take over the family business.
Again, you don't have to take this approach, but it is worth considering. Make sure you really look at all of your options and the steps you need to take when doing business succession planning.