I've been on hrt for 2.5 years with good levels and I've never experienced the fabled girl orgasm. It definitely feels different from how it used too, but I still have the same refractory period, and the feeling is typically still pretty focused on my genitals. It might be slightly more extended through my body and last a little longer, but they also feel less intense than before. Feels more like a sidegrade than an upgrade to be honest.
Theres no way to tell when and by how much your orgasms will change, but I can certainly share my personal experience.
Im about 3 months into HRT right now, and i have noticed some gradual changes in how my orgasms feel. It started with a gradually more "full body" experience and also i started to have better results using a vibrator instead of stroking. I first started noticing those changes around the 2 month mark, and they have gradually progressed since then. In the last week or so i have been able to have a second smaller (and dry) climax after the first, which is exciting.
For me, the changes happened really gradually, and some changes didn't happen at all (which is normal, because it's not the same for everyone, not even cis women.) It took around 2 years before I started noticing any changes, and around 4 before I stopped noticing any more changes. It can vary a lot though.
It's also worth noting even once you've experienced all the changes, it won't feel the same every time. For instance, for me, it's only a full body experience if it's a good one. Otherwise it doesn't feel much different in nature from a guy's orgasm. It does definitely last longer usually though. Usually around 15 seconds, but it can go up to... well, actually, I've never felt the need to break out a stop watch.
There's some things that for me never changed though. For instance, it doesn't take any longer to build up, and I almost never can have multiple in a row. Although I'm still responsive to stimulation, it just doesn't go anywhere. On very rare occasions I've had consecutive ones, but it's been that way since even before I transitioned.
Also, I've seen a lot of claims that female orgasms are more intense than male orgasms. For me at least, that is absolutely not the case. They feel different, but intensity wise it's exactly the same. I do react more physically, but not because it feels better, rather just because estrogen did that to me for some reason.
I think honestly the line between "male" and "female" orgasm are a lot blurrier than people think and it's not really a useful way to think about it. Not everyone will even experience changes to their orgasms and that's not because there's something wrong, it's just because there's so much natural variance that many women just naturally experience what is often called a "male" orgasm.
I've seen a lot of trans women get really disappointed thinking something must be wrong because they haven't achieved the fabled "female orgasm." Just know that that's a very idealized version of a female orgasm that not even most cis women, in my experience, meet. It's completely normal for some things to change but not others, or even on occasion for almost nothing to change at all.
It's hard to know how everyone's bodies will react, but it's also important to consider the purely psychological effects. Even social transition changed things, at least for me. Seeing myself differently somehow affected the way it feels and how long they last. I started to ejaculate without orgasm, experiencing a more intense orgasm once it finally happened. Orgasms are confusing.