Have you started looking for preschool/daycare yet? Usually in the US, preschool starts at age 3, and they must be toilet trained (not wearing diapers). Before that age is usually called daycare. If you work, you would want daycare anyway, as preschool hours are not full day- more like 9 am to 3 pm. At age 3 and up the daycare will have a school curriculum, teaching letters, numbers, colors, shapes, etc. Typical daycare hours might be 6am to 6 pm, though, allowing for a full working day. Most parents do not leave their kids for a full 12 hours, but that schedule accommodates those who start work early or leave late.
You should also call the school district that you live in and ask what options they have. Some school districts have 3-4 year old programs that are full day, that you typically pay for but may be free for low incomes families. These often have the advantage of school bussing. My daughter has attended a program like this since age 3. For full day, the bus picks her up at 8:15 and drops her off at 3:30. The advantage of school district programs is that they are often cheaper, and they often have better educated teachers. We pay 400$ vs. about 800$ for a daycare center in our town.
In the mean time, find your local library and ask if they have story time. Most libraries have this on weekday mornings, and all the neighborhood stay at home mothers and fathers and nannies will arrive for an hour of stories, songs, and crafts. It is a great place to expose your child to English, and meet neighborhood parents and kids. If you tell the other parents you are new and need help finding schools and children's activities, they will probably be happy to offer advice and opinions.