Alright well can i get in troble for got out w/ a girl thts 15 im 19 ?

we been talking n I really like her but her parents don't want me talking 2 her cuz of our age they said the were going to take legal action if we didn't stop I she lives in hammond indiana and I live in chicago I know that both states have a different age of consent but am I doing something worng or illigal. Ps... we dnt even see ea other we talk on fb any info or adbise would lik u give will be thanked