Well, not all hymens are the same (click here for educational pictures! link ). Depending on the size of her hymen, it is possible to finger someone without it breaking, and sometimes it will stretch rather than tear. There's also a chance that she doesn't even have a hymen, as some women are born without one, or often the hymen can be broken through other means (masturbation, using tampons, playing sports, etc.). So, to answer your question, it might break, it might not, or it might already be broken.
"Can I finger her good enough if I just use clit stimulation?" Many women prefer clitoral stimulation to vaginal fingering, but it really depends on the girl.
But, the fact that you're placing that much importance on breaking her hymen during intercourse seems kind of creepy, and even selfish to me. Why is it important? Would you avoid pleasuring her by fingering her vaginally (if that's what she wanted) just so you get to break her hymen during intercourse instead?