John Mueller from Google said on Twitter that if you are building a new site, then you should most likely go HTTPS from the start. I don't think anyone would argue with that. Switching from HTTP to HTTPS can have its challenges but starting your site off on HTTPS from the onset makes a lot of sense.
Here is John's tweet:
If you're setting up a new website, just use HTTPS. It's not required, but it's a signal, and it's easier to do it from the start than to add it later.â" John â.o(â§â-½â¦)o.â (@JohnMu) February 13, 2018
I've moved many many sites from HTTP to HTTPS without any major issues but there are checklists and work that needs to be done to make sure everything was done right. But any new site, starting with HTTPS makes it way easier.
So if you are launching a new site, go HTTPS from the beginning, it will save you a lot of trouble in the long run.
Forum discussion at Twitter.