There are many role models in astronomy today. Which you choose depends somewhat on your interests. For example, the Director of the National Optical Astronomy Observatories is a woman. SHe manages a number of telescopes in Arizona, New Mexico, and Chile. There are women who are full professors in major universities and many have senior positions in government agencies.
Women become astronauts in the same way that men do.
I cannot predict if women will be on the first mission to Mars, but it would not surprise me. If there are several trips to Mars, I think that it is almost certain that a woman would be included. Yes, I think that I would have enjoyed both space travel and walking in space although I am not sue I would have enjoyed the various problems before hand. One last question. We do not know if the universe will ever collapse.