American Guinea Hog sow too old?

Hi all,
So I just put down a downpayment (they are asking $250) on a mama AHG, but now I'm kind of worried because I think I acted too impulsively. The sellers say that she is 4-5 years old, and "doesn't see too well". She's had 3 litters and is probably pregnant again since she has been around a male and isn't going into heat anymore.
SO, my questions are:
Is a 4-5 year old mama pig too old to buy?
How many litters can an AGH have in her lifetime?
Will she be able to be nice to other pigs, as I am planning on buying a younger pair as well?
Is it a bad sign that the mama pig is only 4-5 years old and already has lost most of her sight?

Thank you so much everyone. Pig are new to me, and I am SO excited to dive into it.
!!!

A single litter will easily pay for the $250 purchase price, and if you decide she's all done you send her to the locker.

Sounds like a good purchase to me.

At $250 that is a low price and probably worth the meat alone. If she has a litter then you are that much further ahead. Frankly four years old is not very old. We've had lots of sows go to six or eight years.

I purchased my pigs from the president of the association and when I went to pick them up he was showing me his pigs, he had a pair that were still breeding that were over 10 years old and maybe 15 I forgot but it blew me away how old they were. So that being said I think you did fine with your purchase. We just had our first litters a month ago with a total of 9 piglets and they are doing fine. Good luck

No one has mentioned that hog is nearly blind...wouldn't that mean extra care in getting her food?

Actually, a blind pig is not a huge deal. I've had one that was blind in one eye and one that was totally blind. Neither seemed fazed by it at all. Yes, pigs use their eyes but they're not like us. Humans are extremely visually oriented and then auditorial oriented. Pigs are primarily olfactory oriented. After that is touch, primarily with their lips and tongue. Out in the wild a blind pig would probably die to predators but on a farm it is not a big deal even on pasture.

That said, I wouldn't buy a blind gilt or sow unless she had fantastic genetics otherwise and the blindness was not genetic.