If you've got enough Stars through logging in, yet when you attempt to claim your Star Reward, you're receiving a message that says, "You haven't played long enough to collect this!" it quite literally means you have not spent enough in-game time within Adopt Me to claim the item.

We implemented a play-time limit to ensure these rewards are meaningful for players' hard-earned efforts of logging in and playing consistently. This meant players couldn't just log in to all of their alternate accounts and be rewarded quickly, as this would ruin the value of the rewards due to them being easily obtainable. As such, when players log in to claim their reward, they must have played Adopt Me for a set amount of time.

You'll need to play Adopt Me for a few hours to receive your reward; as a matter of fact, you'll need to have played 90 seconds per Star needed to claim. As an example, you need to have played 12600 seconds or 3 and a half hours to claim the Human Bubble which is worth 140 stars. The following chart details the number of stars and subsequent play time required to claim the items. 

Let it be known that we don't expect you to play for 16 and a half hours in one sitting so you can claim the Golden Egg, as it takes a minimum of 180 days of consecutively logging in to earn enough stars for this. Instead, you can play for 16 and a half hours over the course of 180 days.