how common is a second missed miscarriage??

What are the chances of it happening again?? We want to try again and are way more educated as to what can happen now obviously. We lost our bean at 8 weeks but didn't discover it until 10 weeks. I am 36 with 4 older kids 8-17. Should we give up? Will this happen again? What can we do to increase the odds? I've been tested my reserves are fine no thyroid no issues. Am I just too old?