Hi and welcome. All the salient points have been covered here. Although worth reading all the pig postings on this site some very helpful information from lots of very experienced people is available on these pages.
I love tammies but find them too fast for my advanced years.
After my experiences with Hilary, a lovely/beloved sow with a very definite mind of her own, the speed of a race horse when annoyed, and teeth to make Dracula cower, I would very strongly suggest you get plenty of experience of handling pigs before embarking on any form of breeding.
If at all possible gain some hands on experience of farrowing before buying your sow. I would strongly recommend you pay the extra and buy a proven, well handled, gentle sow from a good breeder (loads of good breeders on here) preferably local to you who can and will help out should you require it. If your first farrowing starts in the middle of the night and needs help you will need all the confidence and trust between you and your sow to intervene.
Please though dont be put off, I wouldnt be without H for the world, nor would I give up pigs, they are so totally addictive. Enjoy your piglets, enjoy your pork (totally fantastic experience) and then enjoy a long and happy time breeding pigs .