Hello Friend, Good that you are seeking a help.
She might need some time to come out of that failure. She may be resistanting for one more relationship as she is still undergoing the transition phase or holding her emotions with that first love. I can understand your worries about her age factor, but equally think about consequences of forcing her for a marriage without she being ready . It will unnecessarily spoil two individuals life.
Solutions here is to get and give her some counselling support to accept the failure and make her realize the need for a long term relationship and how to move on in life. She need that guidance.
Next Steps
Feel free to reach out to me online or f2f for a detailed discussion and to explore a suitable solution to make her realize the need for another relationship in long-term..