Can I enter Thailand on a 30-day exemption and apply for a Non-O visa based on marriage?

And what is the country of origin of your passport.

Different countries have different entry rules, but as long as it is the same country as mine, you might be able to do it.

Not every Immigration Office has the clearance to convert to Non Immigrant visa, go the easy way and apply for the visa before travel.

Get 90 days on entry and have time to arrange the requirements to apply for the 1 year Exension of Stay.

Yes, it is possible for you to apply for an initial in-country Non-O visa based on marriage to a Thai for 90 days, then a following 1-year extension based on marriage by meeting the requirements from the local immigration office you are going to apply at. Those include proof of finance, remaining minimum or maximum days, marriage documents, etc. You need to check the requirements from that office.