My large breed girl hasn't had a season yet at 17 months. Is there anything to be worried about.

Have you asked her breeder when her mother had her first season, and what is common for the breed? MY IRWS had her first season at 16 months (my dalmatians usually have their first season at 8 months) but as the setter's mother had her first season at 3½ years old, we were quite surprised it was as soon as 16 months!

> Have you asked her breeder when her mother had her first season, and what is common for the breed?

Good suggestion - when my Whippet showed no sign of coming into season the first time, when she was a similar age to when my Bassets started (around 8 months) I spoke to her breeder and was told that her half-sisters and mother came in at around 18 months.   I left it to 11 + months and then asked my vet, who had refused to spay at 6+ months (citing bone development issues, and potentially spay incontinence), to go ahead.   I had an elderly unwell male at the time and he didn't need to be under the same roof, (even if in another room) as a bitch in season.   In fact I made arrangements for her to board with a nearby kennel if she did come in before being spayed. 

Bitches do often follow their mothers with this although I had one (Basset) who came in bang on 6 months, and then started cycling at 5 monthly intervals.   I had her spayed!!

My flat coat was about 2 when she had her first season and had them randomly thereafter .
When I mentioned it to her breeder she told.me her mother was similar until she had her first litter.
As.mine has never been bred from I dont know if that would have changed anything.