Step Up Slowly
A great relationship is going to last decades. That means that every step should be savored and explored. If you rush to the very last step, just what are you going to look forward to for the next years? There are people who are dating for years who get bored, because there is nothing new next!
If you truly believe you two were meant to last, then there is no reason to rush. In fact there is every reason NOT to rush. Take every step as slowly as possible, exploring every possible way to do it. That way every new thing you do is as amazingly fun and special and new as possible.
Keep track of every new kiss you try, ever new location you kiss in, and so on. The more slowly you go, the more you appreciate every new change.