Can I leave Thailand to visit the US while on an ED Visa without losing my visa status?

I am a US passport holder in Chiang Mai. I’m studying Thai and I got my ED Visa in Vientiane earlier this month (I used Aya Service, easy enough). Question: my Ed visa is only for 90 days and I understand I have to go to immigration to get an extension every 3 months up until one year, or can I also leave the country and get a stamp? I was told by someone at school that I can’t leave the country to go home to US, and told by someone else that I must leave the country during this year. So which is it? I would like to visit the US this year, but not if it cancels my ed visa. Thanks!