Mewing is indeed a fantastic technique, and you've already seen some impressive results in just three months.
The size of the tongue can play a role in oral play, as a larger tongue may be able to cover more surface area, potentially increasing the sensation for your partner. However, the actual effectiveness of tongue size in oral play is relatively minor compared to other factors like technique, tongue flexibility, and the overall fit between your tongue and your partner's mouth.
In general, it's more about the way you use your tongue to create sensation and pleasure rather than relying solely on its size.