Mine were also 30 to 35 days and started to get shorter. By the time we started trying they were 23-25 days long!
Cycles start to get shorter with age and it's a sign of decreasing fertility.
I'm on Cycle 6 and I've spent the past half year reading a lot and stalking the Fertility Friend's thousands of charts to see what works.
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For improving egg quality and your chances to get pregnant:
I narrowed it down to taking these supplements:
CoQ10 - it comes in either Ubiquinol (expensive, hard to make) or Ubiquinone (reasonable price, stable)
The eggs take months to fully mature but the chromosomes divide in half right before ovulation to make room for the male genetic material and that process takes A LOT of cellular energy. With age the cellular energy starts to go down, hence genetic errors and miscarriages.
This supplement is the best thing you can do to improve egg quality. I found that it takes away fatigue, so that's a plus.
I was taking 400 ubiquinol but I switched to 800 plain ubiquinone (more stable format, so it's cheaper, but you need twice the amount)
Methyl B12/Methyl Folate - both are needed for implantation and pregnancy (some can't absorb folic acid)
Evening Primrose Oil - regulates the cycle and increases the cervical fluid (Egg White fertile fluid). The swimmers need good fluid to get to the egg. You'll notice a lot more cervical mucus (CM) after you take this. Start when you get your period. STOP when you ovulate.
I started on those a little over 2 months ago after I had a chemical pregnancy and I decided to focus on egg quality. My cycles are now back to 29 to 30 days with better charts.
I found the brand Jarrow Formulas has all 3 and they're the best price and quality.
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For catching you most fertile days:
Just watch when your fertile fluid looks watery and start using the cheap internet OPK strips.
And catch those 4 fertile days.
You'll notice watery fluid around 4 days before ovulation - so "O-4"
Then you'll notice egg white fluid a couple days before ovulation so "O-2" (Peak fertility)
The day you get the FIRST bold positive OPK is the day before ovulation - so "O-1"
The day after, assume it's ovulation day. So "O"
From this day on the "Two Week Wait" to test starts and you can count 1 DPO, 2 DPO. and you'll notice creamy CM or dryness
Ladies start testing around 8 to 12 DPO.
Get a notebook and take notes like "Calendar Day 9, I notice watery CM, negative OPK, BD (baby dance/sex)" so that you can start to see a pattern that's unique to you!
On the bottom of that page tape the internet cheapy OPK
to see a test line progression (click on this link)
Good luck! Take a fun approach to it, like a game and one month you'll win! Since TTC can be stressful. Just enjoy the process. Good luck!