Hi @Mit,
I was little bit scared when I saw the title 
.
Joke aside, The trigger module in Make primarily has two types, INSTANT, and ACID. Instant means that whenever there is a new event it will immediately pick the Contacts and Watch will pick any new data that has been added/updated(based on the Module) during the scenario scheduling time, i.e if you are running it every 15 minutes, in theory, and if it is working correctly it should pick up the data that was created in between last run and the current run. You can find more regarding this here and here.
Regarding the contact you are getting old, try right-clicking the Watch Trigger and then Choose When to Start and Select From now on and see that fixes the issue you are getting.