I spoke to my dentist about this and she said they’re not expected to spit it out at that age. Just use the recommended small amount and it’s fine. My eldest figured it out when she was about 2.5/3 years old. Both mine use aquafresh
We use the aqua fresh milk teeth one
I used to work in the dental industry. It's advised any toothpaste with fluoride in can be used. As it's fluoride that stops the cavities. 0-3 years old have only a smear of toothpaste. Children over 3 have a pea size. Only having a smear of toothpaste means they don't need to spit out the toothpaste. As there is not enough toothpaste to spit out. Never rinse the mouth after brushing with toothpaste as it washes off the fluoride.
We don’t really get our 15m to spot just brush teeth and that’s it. Hmm think we use a Colgate one