It is not uncommon for the courts to ask for further information or to reject an order if they are not satisfied as to fairness. Was there any cohabitation prior to the marriage? Thus could make a difference.
If you are both happy with the agreement then you can write a joint position statement explaining how you reached the agreement and why you believe it is fair. This can be sent with the supporting statement of information (D81).
If you have had legal advice that will strengthen your position. You can get a fixed price legal financial consultation via this site. Have a look at the services tab or call the helpline for advice.