You just need to realize that such an important grief in her life takes precedence over your excitement about the budding of new love. It certainly DOES hurt to have your blossoming affections interrupted! But that is YOUR emotional experience, and you can't expect to pull her away from a time when her family-centered emotions are all-powerful in her life. That natural family crisis and milestone is NO reflection on how she feels about you; she just doesn't have emotional room for directing her feelings outside of the circle of her family for a while. As a young man, you're probably not nearly as much centered in your emotions and family-oriented feelings as she is. So give heer a chance to tell you about it when she wants to, but don't insist that she share her grief with you, when you've never met her uncle. And don't indulge in your hurt feelings because of the ACCIDENT that her family tragedy has interrupted the growth of her feelings toward you. It's particularly important that she needs to NOT feel obligated to keep you happy until she is ready to share some of what's happening in her life with you.
You might be able to help her continue with her grieving process if you asked her to tell you about her cherished memories of her uncle. But it's important for grieving relatives to be able to proceed with their reckoning with the deceased at their own pace, and NOT to be pressured into "getting on with their lives" for other people's convenience. Your own reassurances that she's a shining light in your eyes are all she needs. You're doing fine, and if you can remember what losing a valued friend or relative was like for you, you can draw from that.
You might enter a deeper level of emotional communication with her, If you CAN gently engage her in sharing some memories about her uncle with you, or telling about key family experiences during this time (grief is a time for family renewal, and family relationship ruptures may be eased or get worse at these times). But you'll need to let HER take the lead and not push her towards intimacies that she's uncomfortable with. Sometimes a Hallmark sympathy card is a good gesture, because it doesn't demand any intimacy in return.
It's not selfish to be more acutely aware of the painfulness of your budding feelings being interrupted--because that's a very strong recipe for HURT FEELINGS: Not because you want to be hurt, but because the interruption of excitement and the intense joy in anticipating more together time with her is a natural emotional dynamic for generating the inborn core emotion of SHAME, in this case experienced as Hurt, Embarrassment, Awkwardness and Alienation (from her)--even though neither she nor you intended for this to happen. And Guilt is also a close relative of Shame, so you are feeling guilty (which you're calling "selfish"). She's ALSO likely to feel Guilt, which she could attribute to disappointing you (even tho that's NOT why she's feeling it: She'll feel guilt, awkwardness and other shame-related feelings because Shame-emotions are naturally triggered by the unexpected&unwanted interruption of the network of love&joyexpectations in her family due to the sudden loss of one valued member. And of course she's NOT happy; she's bouncing back and forth between many emotions and reacting to the tumult in her family. (So you can't expect to make her happy, except to show her respect and comfort.)
She will probably make some contact within a week. American culture is pretty bad at handling the social aspects of grief. (Where's GRIEF belong in the "Pursuit of Happiness?") Because the cultural imperative to "Be Happy" is INTERRUPTED by grief; so most people are unsure about what to say and when to say it. So they act awkward and avoid mentioning the subject of grief and loss--which makes the grieving person feel like she's not supposed to be feeling what she does feel, so her personality gets split in two. (Ultimately your goal could be to give her respect and attention for BOTH pieces of her personality--the "normal life" part, and the part that's sometimes focused on her loss, and her past connection with her uncle, as well as other family members who are perhaps more disturbed than she is. For deciding how to communicate with her, much depends on how close she was to her uncle personally--so you might respond to her first contact with you by asking how close she was to him--and if she indicates that she knew him well, invite her to tell you about him whenever she feels like it. If she doesn't life with anyone else in her family with whom she might share reminiscing and hence processing her own grief, then your asking her to introduce him to you--as a way of knowing her family, might also further your acquaintanceship with her.
Women in American culture form their most valued friendships with other women by exposing their vulnerabilities; and she MIGHT be vulnerable now if she's feeling sadness and/or overwhelmed. Many young women don't want to show much vulnerability to men, and men don't naturally show their worries or suffering to other men. But if you can sense her feelings and approach her with gentleness and some trust in your own vulnerable feelings, your relationship could develop a different level of emotional connection way sooner than normal for early dating.
As a matter of fact, I've been developing a novel theoretical explanation of love through the mechanisms of its "Emotional dynamics" since 1996. I started teaching that to my Psych of Relationships classes in 2005, and in the first semester, one male student told me in class that "all of my relationships that began with good sex and excitement and enjoyment blew away with the wind in a few months. But those that had lots of different emotions in them, including troubled events, THOSE are the few that lasted much longer." So expressing, coping with and containing Shame emotions (as listed above), Distress & sorrow, and also Fear and Anger, as well as the positives of Excitement, Joy, Surprise and Lust,--communicating and living with that full-color palette of emotions is what builds relationships that really last. Most younger men are too incompetent with many of those emotions to get into them until they're a few years into a relationship or have had 5 to 15 years of half-human intimacies to gradually get initiated--or they need some major turmoil in their lives (like I had with my father once I left for college @ 16, and esp after my mother died when I was just 23) to push them into emotion-tutoring via counseling or study.