Both methods have their advantages and disadvantages, and which one is better for you depends on your playing style and preferences. However, it is generally recommended to learn to position all fingers at once and press down simultaneously, as it can help you play more efficiently and accurately in the long run. When you use one finger as an anchor and then follow up with the other two, it may lead to inconsistencies in your playing, as the first finger might not always be in the same position. Additionally, it may slow down your playing and make it harder to play more complex chord progressions. On the other hand, positioning all three fingers at once might be challenging at first, but with practice, you can develop muscle memory and improve your finger dexterity. It can also make it easier to transition between chords, as your fingers will be better synchronized. Overall, you can continue using your current method for now and gradually work towards positioning all fingers at once. It is essential to practice consistently and be patient with your progress, as mastering guitar chords takes time and dedication.