Big belly or just more fur? Nipples still white

My friends cat is getting thick around the middle, past the ribs. Her belly is not 'hard' but squishy, for lack of a better word. Also I have noticed she has gotten more fur around her belly lately, though this may be due to her being an outdoor cat and the winter weather. She has been looking thicker for 3 or so weeks now. Her nipples look white, though two look reddish pink. No change in size of the nipples, still same size as a male cat. I had read where the nipples should be pinking at 3 or 4 weeks. Have you ever heard of a cat having kittens and the nipples not changing until the 8th or 9th week? I have seen a pregnant cat before and they look heavier than she does, though she could be just carrying one, or early into the pregnantcy. Though, like I said, she has been this thick for 3 weeks now, and getting a little thicker. He and his neighbor was hoping she was pregnant since the tom that would have mated with her has passed away a few weeks ago and the owners were wanting a kitten of his. If she isn't pregant, he was going to get her fixed. Also, he says she has never been in heat as far as he knows, she is only 7 months old. She has never done the yelling or calling, and not running in place when you scratch her top back. Though I thought I had read where it didn't matter if the female went into heat or not, if the male still tried to mate with her. Though there is no evidence he ever did.

I would imagine that if she were pregnant her nipples would be larger. When my cat is in heat her nipples are very enlarged so I would imagine that being pregnant would have just as much of an effect.

Thats what I was thinking. I am thinking she has just packed on some extra weight and fur for the winter.

I doubt she made it to 7 months without having one heat cycle, usually they start at 4 months.
It's not a good idea to let an unspayed cat outside. Keep her inside until she is spayed, if she is not pregnant she will be.