Honestly? Long story and a different take on it but it might put things into perspective...
Our third unplanned baby was a huge shock.
We had only been together 6 months and I have PCOS and had huge struggles getting pregnant with my first 2 DC. DP never ever wanted children of his own (but was keen to be step dad to my two) and I had made peace with never putting myself through the emotional destruction that comes with TTC again.
Then SURPRISE.... baby number 3 was conceived. I was in total shock and extremely excited but terrified of DP's reaction, knowing his feelings about having his own.
He was distraught for the first couple of days and sunk into a terrible state.
Then he seemed to turn it around when I went for an early scan and our baby was in an 'unknown location'. He saw how petrified I was, looked me in the eyes and said "I understand you now".
Anyway, my HCG shot up and I wasn't experiencing any pain so our worries were over and we went full steam into selling our flats (we lived separately) and buying a house together with an extra room for our new addition. We were thrilled and we made so many plans. Money was going to be tight but we would figure it out as we went along.
Then at a later scan, we discovered our baby's heart had stopped beating a couple of days before.
I can't even begin to tell you the pain that caused us.
I never knew how much I wanted another baby until we found out we were expecting our little one.
3.5 years later and we've had two further losses and now struggling with PCOS again.
So, in answer to your question, our unplanned third child situation turned our life upside down. It made me into a horrible bitter person and I've no soul left. I would give anything for a third child now we've experienced babyloss.
Part of me wishes our third child never happened as I would be none the wiser and would be absolutely fine (as I was before) and enjoying life. But another part of me thinks, despite all this pain and suffering and losing two more babies , we wouldn't have moved into our lovely house and met new friends in a new town, and I wouldn't have had the absolute pleasure of carrying our three little ones even if they were short lived.
I don't believe everything happens for a reason. But I do think that you make what you can out of difficult situations and life can change drastically at the snap of a finger with no control whatsoever.
We are also due to get married. Our wedding is next April and we have still continued TTC despite this. If I had got pregnant in my last cycle I'd have given birth a week before the wedding (c-section!) but it didn't happen sadly.
My advice to you would be to go with it and see what happens. I wouldn't cancel the wedding either. You simply cannot plan around these things. Just go with it and please enjoy every single moment of it. You are so very very lucky. I hope things work out for you with the baby and congratulations on the engagement! xx