Best way to get into investment banking without experience

I am a rising junior at a semi target (think McCombs or Ross) and I have no internship experience within finance. My parents started a new business and I have spent the past two going on three summers helping out in whatever capacity I can. The closest thing to experience I have is the personal portfolio I have been managing. I went to several info sessions and networking events and have built up a working knowledge of IB. My freshman year dinged my GPA pretty badly and I am now sitting at a 3.4 overall. Without internship experience and a subpar GPA, do I still have a chance of landing an IB internship next summer? If not, which fields should I consider?

Also, IB applications just opened up and spots are filled on a rolling basis. Should I send in my app ASAP or wait until I have networked with a few employees?