
Bitches vary widely as to when they have their first season - it's usually between 6 months and a year in the average-sized bitch (giant breeds tend to be later, sometimes not until 18 months or even a bit later!). If you're going on holiday shortly I wouldn't have her operated on beforehand because of all the post-op care required - it would be unfair to a boarding kennels to have to cope with that, and if you're taking her with you, you could have problems finding a vet where you're staying if there was an emergency.
Is she showing signs that her season is imminent, such as temperament changes (just like adolescent girls, they can become moody!), is her vulva swelling, is she urinating more than usual?