Hi, I don't know if it is too late to respond... but i just got married to my husband (who is Mexican) in Mexico a month ago... it really depends on which part of mexico you're getting married, I think each office works a little differently and sometimes they can even misinform you. For me, I'm Canadian with a Hong Kong birth certificate, I didn't have to get it notorized in Mexico or anything like that, as long as the birth certificate has your parents' name clearly stated and your name as well, it should be fine (at least for me it was).
Also to apply for the permit to get married married with a Mexican is a lengthy process, you have to apply for the permit and it can take 15-30 business days; it might be faster though, they told us to return a month later, we went back only to find out that they had it over three weeks ago... so we could have gotten married on the date we wanted.
Overall it wasn't too bad, just have to wait. If you're living in Mexico its not difficult, I find the wait a little too long if you're just there to visit. I had 2 1/2 months off work so it was fine for me
I hope this will help you.