Yes, it's true that some children can train as early as 18 months, but I would say that it is highly unlikely even fore a SAHM. To be certain she is ready, me ped recommended looking for these signs:
Your child tells you when she is wet or poopy
Your child takes herself off to "hide" when she's having a bowel movement.
Your child can stay dry throughout nap time and/or night time or for more than 4 hours.
Your child tells you she needs to go potty before she goes in her diaper.
Lost of toddlers show interest, and some even get lucky going on the toilet if their parent lets them try, however, at this age, it is more luck and novelty as most "new" toddlers can't control their bowel movements, which is more of a true potty training readiness sign.
Training too early can often backfire on insistent parents, so it is better to wait a little longer and be sure your child is ready to ensure your and your child's success.
With good, consistent potty training and the right timing, it should only take a couple of weeks to establish a successful daytime potty routine. Nights usually take a little longer. Having said that, accidents can and will occur for at least the first year or two after potty training (especially during the first year) while a child learns that going potty can't always wait until they're done playing or that it sometimes need to be done before they're truly ready to go (as in the case of going the bathroom before taking a trip) or they learn to hold their urge a little longer.
For SAHM, it is a full time effort for those two weeks of initial training, so with you working full time (I am assuming your child is in day care), it requires even more of an effort as you coordinate with your husband and day care provider.
Having raised 4 children, coordinated with 7 siblings on potty training their 20 children, and getting first-hand advice from a sibling who's a pediatrician, I would recommend waiting until your daughter is AT LEAST 2 years old. 7 months may not seem like a long time, but for little ones, it is a huge step in maturity. Just think of how much your daughter has changed in the last 7 months! Having said that, I wouldn't recommend setting an age to potty train just yet. Watch your child, look for all/most of the signs I listed, and when she's truly ready, you'll find potty training to be easier and better yet - successful!
Feel free to email me if you'd like any further help when you actually begin potty training.