Hello David, Precocious and Premature are conceptually similar words but are usually never used in the same context or are replaceable with one another. Precocious generally has a far more positive attitude and Premature has a far more negative connotation. Precocious is usually used in regards to children who display exceptional abilities and usually implies an impressive trait despite being young or inexperienced. If someone says "What a precocious child!" they are usually implying the child is talented or intelligent for their age. It doesn't necessarily mean they're exceptional, merely that they're performing better than their peers or similar age groups. Premature, however, is far more negative, usually implying that something occurred too early and, because of this, suffers from developmental issues. An example is "I pulled the pizza out of the oven prematurely," which means the pizza is not cooked through yet and is so lesser than a fully developed pizza. Another example is the scientific term for "premature ejaculation" which refers to a sexual partner who reaches climax often far too quickly for them to enjoy the sexual encounter or for their partner to reach climax as well.

just depends on the affect one wants to incite-- premature has a slightly negative connotation & precocious the opposite-- even slightly mysterious in the case of the latter. beckham for instance would be the former ;)