It's actually VERY normal for babies around the 3/4month mark to struggle connecting sleep cycles & to only nap for 45mins, so it's not really something you need to do, more that time will help them mature enough to do it.
(She had a baby nurse who spoiled her so I'm trying to break the habit as well).
babies don't get spoilt, they can be overstimulated by too much care & attention, but they aren't spoilt, so it's not a habit you need to break, more something to be pleased that she was able to have that human connection.
Rather than be stressed by the short naps, do what "works" if she wakes at 45mins & you know she will resettle in a sling then do that... the time will come when she can join the cycles together.
I found with my DS2, that it was better to embrace the short naps at times my DS1 was awake & do things together (get out of the house etc) & then focus on trying to get one long sleep when they both napped at the same time, so at 3mo, my DS2 was 45min nap, 45min nap, 2.5hour nap, 45min nap rather than 3 longer naps. I found that naptime when his older brother napped & bedtime were the only time I didn't make it "easy" for myself & just accept he'd have a short nap.