Actually you said that 3 years ago
shortly before her first breakthrough in Australia at the end of 2010.
And my backtracking was in April last year, before her second one in the US hard court circuit
She is obviously a late bloomer.
This is also proven by the numbers
: out of 118 players on the list (including her and Japanese Nara who also broke in), Julia is only one of six to crack the top 100 after celebrating her 23rd birthday.