Don't forget at that price it isn't a multiple entry, so if you leave the country remember to get a reentry permit. Congratulations on getting the extension relatively hassle free.
I don't know how close you are to Kalasin, but I have only been treated well there. Also in the three times I have been there, it has only been me or one other.
Remember later you may want to apply for permanent residency or even citizenship. I believe they are based on how long you are attached to your original visa via extensions. To change to an Ed visa you might be breaking that chain, better to keep it simple. Good luck with your studies.
Go to Savannakhet, you can get a one year multiple entry Non O based on marriage, no financials required. You do have to leave the country every 90 days, go to a bordering country stamp in, stamp out and back to Thailand.
The easiest would probably go to Suvanakhet and apply for a non O multiple entry visa based on Marriage, no financials are required. However you do have to leave the country every 90 days, but you can do an out and in.
The closest spot for you to stamp in and out is Malaysia. If you want to fly there are or at least used to be flights from Phuket to Penang, do you might want to take advantage of the convenience.
Just did my one year extension based on retirement at Kalasin Immigration. All my hyped up anxiety was for nothing. I arrived at 8:15, office opened at 8:30. I was the first and only customer at the time. There was a nice lady, very young more like a girl, she spoke at least all the English she needed to deal with me. I handed her my passport and copy, my letter of income from the Canadian Embassy and copy, my yellow book and copy, and my pink id card and copy. She didn't like the copy of the pink id card so made her own. She asked me if I had a wife, I said yes but I wanted to do the extension of stay based on retirement. I then handed her a copy of my wife's id card and blue book, not sure if they were needed, but she took them. I also gave her a hand drawn map to my house. That was it. She gave me a couple of forms to sign talking about the penalties for over stay. She was young, but obviously had the authority to authorize the extension. In and out in about 25 minutes, very good service. I gave her ฿2,000, she gave me ฿100 change, that I put in the top box. Kalasin Immigration has got some negative reports, but I saw only positive.
Oh yes just to make it clear I was extending an original non O 90 day Visa from Savannakhet, this made my thirteenth extension.