It often depends on the source. Some sources give them out all year long, with new starters available nearly daily. These are sources who give out more common pokémon that are easily obtainable throughout a given region.

However, professors are special cases, as regional ones often give out a set of three starters (one grass, one fire, and one water) designated as “official starters” by the Pokémon Association. These may only be given out once a month, largely because it takes time for a breeder to obtain and hatch eggs of each species, as well as ensure that each hatchling is suitable for battle.

In rare cases, a professor may give out something other than their usual three starters, but usually, these are fantastically unusual circumstances. For example, Professor Oak once gave a boy from Pallet Town a pikachu that was extracted from someone’s home and scheduled to be released into Viridian Forest, but due to the rather … unique case of the boy, it was given to him as a starter instead.

Well, anonymous, that depends. What would your boyfriend’s sister want? If she would be interested in a fairy-type, then there’s actually nothing that would prevent you from giving her one. In fact, given her shyness, some of the ones who do well around humans, such as jigglypuff or marill, may be excellent choices for her, as these may encourage her to communicate with others (rather than run away at the first sight of a human who isn’t her). In fact, marill’s secondary water typing may even give it the advantage in some regions, particularly those where the first gym is of the rock type.

Otherwise, there are quite a vast number of pokémon that would be ideal for people who are otherwise rather shy. The traditional starters themselves are often trained to handle people of all dispositions, including those who might not be comfortable communicating off the battlefield. Of those, grass-types tend to be the calmest and least challenging in most regions, and bulbasaur and chikorita are widely known for their ability to calm those who might be in uncomfortable situations (including socializing).

If, however, the traditional starters are not accessible to you, it would then depend on your region or on which breeders you know. By and large, the more common the pokémon, the more comfortable with humans they are. Naturally, they may also be challenging starters, as extremely common pokémon such as rattata may be weaker than most other available pokémon. Thus, giving your boyfriend’s sister one of these as a starter may do more harm than good for her self-esteem, as early battles may be difficult for her. On the other hand, they also tend to be easier to tame and quicker to train than rarer pokémon, as their requirements for care tend to be easier to meet. Nonetheless, I wouldn’t rule out rare pokémon entirely, either. If you can obtain them, a fair number of them—such as meowth, pikachu, growlithe, or eevee—are both extremely friendly and wonderful conversation starters, meaning it’s more likely that someone would be willing to break the metaphorical ice with a trainer who owns one of these than anything else.

The point is, it’s difficult to offer specific advice because, really, every pokémon may be a suitable starter. I would simply avoid any pokémon who’s also notoriously shy, lazy, or difficult to handle, and many of these are listed as such in their pokédex entries. Conversely, for someone who’s shy around new people, she may fare well with pokémon who are more well-known for being friendly or loyal.

But above all else, you may simply want to ask her what pokémon she would most like to train. Matching her with a partner she wants to bond with will help her feel more comfortable with the idea of training and battling. If she can reach that point, she’ll be able to communicate with others the best way trainers know how: by battling.

Best of luck to you and your boyfriend’s sister!