Dress query

Ok so I’d really like 2 dresses - one for the day and one for the eve. I haven’t gone dress shopping yet but have found a dress I absolutely love in a sample sale which would be my evening dress.


I’m less precious about the eve dress in terms of having an experience and trying it on. I was originally thinking of getting it online to be honest.
My question is... am I being too hasty buying a dress before even getting my main dress?! I don’t envisage they’ll be similar. On the one hand, the dress is reduced by £900 and now discontinued so it’s really a one time only chance. On the other hand, my wedding is a year away... will I change my mind?
I should add - I can return it within 3 days if I don’t like it and it can be altered.