I questioned inviting kids too and then I remembered that some of the kids are my cousins. Not wanting the distraction I am still inviting them. So its up to you. If your buget allows kids and you really want them at the wedding invite them but I'm sure people will understand if you can't afford to have the kids there. Another opition would be having a small party before the wedding with all the kids and then let them know that they will not be able to come to the wedding to let their parents have a night out without them.