Nope. It isn't okay. Like it or not, she is still legally married and she is off limits. Emotionally, she is still invested in her marriage. She has a lot of grieving to do, a lot of baggage to handle, and the entire divorce process to go through. She's a LONG way from being ready to date.
I'll tell you what I've told everyone who ask similar questions. When my husband and I got married, there were 14 couples in our circle of extended family/friends who all got married within about a 15- or 18-month period. A year or two later the babies started arriving, and about a year after that the divorces started. (Hubby and I and one other couple are the only ones still married, nearly 30 years later.) What we observed among our friends, and what we have seen repeatedly endlessly among coworkers and classmates and neighbors, is that 3 years seems to be the magic number. The people whose divorce had been FINAL for at least 2 years before they started dating and at least 3 years before they remarried, are the people whose second marriages lasted. The people who started dating within the first year after a divorce was final, and who remarried within 3 years, usually went through a second divorce within 5 years. It didn't matter how long they were legally separated before the divorce was final. Until that final decree is issued, many people never begin to deal with their baggage from their marriage.
So don't "date" this woman. She doesn't need a boyfriend right now. Rebound relationships are never a good idea. She DOES need friends. So if the two of you can hang out AS FRIENDS, and spend lots of time in groups of people instead of being alone together, you'll both be better off in the long run. Then in a couple of years, when she truly is emotionally ready to date someone, you'll have a couple of years of solid friendship under your belts. You'll know each other quite well. And you'll know by then whether or not this is a woman you want to date and be serious about.
Good for you for recognizing that she needs time to heal and time to think.