What level of college ball did she play, who was she hitting against, and how old was she when she had her best seasons?
The answer is “yes.” MLB will be very skeptical of any woman who claims to be a good ballplayer, and it would be a long, uphill climb. However, in all likelihood no women are good enough.
It is extremely difficult to overstate how elite the top professional sports leagues are. I assure you I have played with dozens of men who are way, way better ballplayers than your wife who are not and never were even close to being major league quality ballplayers. It isn’t good enough to be really good in college; a player, realistically, has to be the best hitter on his (or her) team, and it has to be a team in a solid conference, for them to be an actual MLB prospect.
For a woman to make it in the major leagues would not only require that she play top-level baseball against boys/men basically from Little League on, but would require overcoming a massive, massive natural deficit in physical strength. A solid female athlete of fairly good size - say 5’10" and 170 muscular pounds, which would be about the size of Hayley Wickenheiser, the greatest woman hockey player of all time and an elite softball player as well - would be one of the weakest players in professional baseball. That can be overcome, as baseball has had lots of small guys make it (David Eckstein was a small player of little strength) but we’re talking about a player who’s not going to have home run power and so will have to be either extremely fast or be one of the most accomplished contact hitters in the world.
It’s a hell of a mountain to get over, and your main barrier is practice. Baseball is not a sport you are born knowing, it’s a sport you have to learn, and to be a major leaguer requires thousands of at bats, innings, and fielding chances against the very best competition you can face.