People get all fixated on what size stack they have at what stage of the game. I have played games where I was short stacked the whole time and made it to the final table and placed in the top five, and I have had games where I built a big stack early and kept it all the way to the final table. The latter is pretty rare; I can think of only a couple times it has happened. I have also played a few games where I enter right before late reg ends, with only 10 bb to play with, and I quickly double up a few times and suddenly I have an average stack and I am in the running to make the FT.
I think it is a bad idea to get fixated on this, a lot like putting too much importance on day to day cashes and measuring your performance based on how much money you are winning or losing from one day to the next. That is not a good idea; it is not a great way to measure skill/ability, and it is a bad way to approach the game, because when the inevitable down swings come, you will go crazy after days, even weeks of not cashing at all. You will start to mess with your own head, and things could just get worse from there.
It is not that easy to put ideas about money and winnings aside when you are playing a game where everyone is trying to win a big piece of that prize pool for themselves, and it might even seem stupid to not worry about how much you are winning or losing in the relative short term. But in reality, there are probably zero pros or big money winning players who gauge their success at the tables by how often or how much they are cashing on a short term basis.
When you get a great early start in a tournament, what you should do is continue to play the same poker you always play when trying to win, so it is basically the same thing you should do when you have a slow start and are short stacked; make as many good decisions as possible, and make the least amount of mistakes as possible. These, along with the perpetual goal of always trying to improve, should be your goals in poker. If you are satisfied with your performance when measuring it by this metric, rather than by the metric of only profit/loss, you will keep having fun playing, even when you are not always winning and profiting, and this is crucial to becoming a good player. If you do not always enjoy yourself and have fun when playing, it is almost impossible to keep improving.