reconcile isn't highlighted, I can't reconcile

You have probably selected a group register in the sidebar rather than an actual account. If a group (eg. Cash, Credit Card) has only one account, the registers will look almost identical. Hover your cursor over the group account name and make sure the arrow to its left points down, revealing the account(s) within, or click the three dot icon at the top and select Expand All Groups. Once you're in the actual account register, you should be able to reconcile.