Will a Cavalier's mount grow upon maturity if it already grew from the dedication?

Question

The Cavalier Dedication states:

You must choose an animal companion that's at least one size larger than you, but if the animal usually starts as Small, you can begin with a Medium version of that animal (changing no statistics other than its size).

The section on mature animal companions says:

When you advance a young animal companion to a mature animal companion:

• If your companion is Medium or smaller, it grows by one size.

If a Cavalier chooses a companion that normally starts Small and chooses to start with a Medium version instead, does their companion become Large when it advances to mature? It seems like that's what is suggested RAW but I'm not sure if I'm reading it right.

Is the intent to allow Medium Cavaliers to pick Small mounts, then ride them after maturity, rather than to allow Small Cavaliers to pick Small mounts and ride them immediately?

Answer 1

Yes, you can apply both size increases

There are not a ton of ways to permanently change size, but they are not 'buffs' or anything like that. They can be applied multiple times if you find a valid combination. Abilities that alter size say what they do; things like enlarge typically specify that you "Increase your size to ____".

For the case of animal companions, these are more open-ended (probably because the options to do so are well restricted in quantity and allowance for choosing them). If you are a small Cavalier, you can choose a small Companion and have them start out as Medium. Then, when they mature, they are Medium or smaller and grow to Large.

This only works for small Cavaliers because you must select a Companion larger than you. A medium Cavalier must start with a large Companion, and therefor will not 'benefit' from either size increase.

You must choose an animal companion that's at least one size larger than you, but...