Can your first period only last a day?

I’m pretty sure it can, yes. Periods are wonky, especially during the first year.

How old are you and are you sexually active?

It is normal, especially if it’s your very first period. Don’t fret, and just wear a pad for a day or two, and you won’t have anything to worry about.

@Pied Pfeffer

I am thirteen, so no I’m not

No worries, that’s completely normal.

@sml Thank you for sharing that information. The menstrual cycle can vary greatly, so it is probably nothing to be alarmed about, but you should talk to your mother or guardian about it. Trust me that the conversation can put your mind at ease. When periods first start, they can be anything from spotty to heavy…just be prepared by carrying sanitary products with you and excusing yourself when you feel the urge to do so. You will soon learn to read your body as it changes.

Nope perfectly normal.
@Pied_Pfeffer GA
Tip. Wear panty liners everyday till you can more readily predict your cycle. It will help with any embarressment that may come with unexpectically getting your cycle in a public place where there may be no bathrooms immediately available.
Back when I got mine, there were a few embarressing moments. Pads where bulky so you only wore them when you had too. No such things as panty liners.

It’s normal, as the others have said. I’ve had mine for years, and still sometimes i’d have it on day 1 and 2 for example, and then nothing on day 3 and then some again on day 4, and so it goes. Mine have been changing over the years in the heaviness of the flow, the number of days it lasts, the severity of the cramps, the PMS’s change, the number of days between cycles have varied anything from 28 to 60 days, so it can be normal to have all sorts of changes in any respect of your cycles over time. You can always get a doctor’s opinion if something worries you too much, but expect the unexpected. :)