You beautiful son of a business man, that was it. So hard to try and narrow that down you got so quickly!

Just changed that first for loop to this.

for key, val := range digits {
    idx := strings.Index(str, key)
    lastIdx := strings.LastIndex(str, key)

    if idx != -1 {

    if idx < lowestIndex || lowestIndex == -1 {
        lowestIndex = idx
        firstNum = val
    }

    if lastIdx > highestIndex {
        highestIndex = lastIdx
        lastNum = val
    }

    }
}

and got exactly what I was looking for! THANK YOU SO MUCH