You are setting yourself up for a tough tradition!
Congratulations. My first ride over 50 miles had a sense of "this is a big deal" - even if it's not actually much different than the a hard 45 mile ride. But it does mean you have reached a level of fitness (and/or insanity - I don't pass judgement) to be able to ride for four (?) hours. A Century is within reach (my advice is do a club ride - that makes it seem more like four 25-mile rides, although you will feel tired starting the fourth leg).