To Sell Sooner or Later?

Struggling to make this decision.Initially I decided it would be best to stay put as we have two children and I want protect their welfare,and would then need to sell when the youngest child reaches 18yrs in 3yrs time.However financially is this the best decision?
Ex has agreed I can have all equity.However there is still 19yrs left on mortgage of £256K.Property has been valued at 350k, but thats not to say that someone will pay that for the house.When all moving costs etc etc are factored in will moving and downsizing be a cost effective option?
I bring in a small irregular salary, have a small pension and am in my early fifties .I doubt if I could get any kind of mortgage now, or in 3 yrs.
Does anyone have any advice as to what would be the best option that would make sense financially. Help.

Have you got the agreement with your ex in writing and stamped by the court (Consent Order)?

No not yet , this is what he is saying at the moment .Obviously I am worried he will change his mind, previously he has done and then changed it back again.But I am sure it will happen.Really need some advice about whether to stay put or downsize now from a financial point of view.

You need to get it signed and sealed first. Don''t do anything until you have. After that, you can choose to do as you like with the house, sell or stay or give it to a cats home, it will be totally yours to do with as you please.

I understand what you are saying obviously , but I still need to make a decision as its something that I am thinking aboutand will need to do something about soon.

I understand your anxiety over paying off the mortgage debt in 19 years time but in reality that is so far off I would cast that worry out of your mind for the timebeing.

Attempt not to get into too much correspondence as it only increases the costs which you will be due to pay in the here and now (on income or a charge against an asset such as the house).

A consent order is preferable and less costly in terms of money and emotion.

Well there is no way I can pay off the mortgage and thats why the house needs to be sold and for me to downsize .The questions is , sooner or later.Thankyou anyway.