Are these odds possible or too high?

After our third egg retrieval my wife and I finally have a PGT normal embryo to transfer, which we are so happy about. The grading is 4bb and our doctor has told us we have a 2/3 or 3/4 chance of it working, or around 75%.

Those odds seem awfully high to me and while I trust our doctor completely and have nothing but wonderful things to say about him, I’m wondering if the chances can possibly be that high? My wife is 33 with no known fertility issues; we are a same sex couple and we turned to IVF after 8 failed rounds of IUI between the two of us (4 each).

We are really excited about the transfer which will likely be next month, but it’s been a long journey this far and I’m afraid of getting my hopes up, if that makes sense.